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X-ray fluorescence application in food, feed, and agricultural science: a critical review
Critical Reviews In Food Science and Nutrition
Abstract
Recently X-ray fluorescence techniques have been widely used in food and agricultural science areas. Minimal sample preparation, nondestructive analysis, high spatial resolution, and multiple elements measurements within a single sample are among its advantages. In this review, literature of X-ray fluorescence are extensively researched and summarized from food and agricultural science areas focusing on food safety inspection, food nutrition, plant science, soil science, and Ca-related problems in horticultural crops. In addition, the advantages and disadvantages of X-ray fluorescence comparing with traditional analytical techniques of elements are also discussed. The more advanced technology such as developments of detector, scanning system, beamline capability among others would significantly increase future application of X-ray fluorescence techniques. Combination use of XRF with other tools such as chemometrics or data analytics would greatly improve its prediction performance. These further improvements offer exciting perspectives for the application of X-ray fluorescence in the food and agricultural science areas.
... Performing theoretical calculations from first principles for characteristic x-ray spectra of atoms is an essential part of quantum mechanics, atomic physics, and quantum electrodynamics (QED). Further to studies into fundamental physics, the ability to reconstruct x-ray spectra has industrial applications wherever x-ray fluorescence (XRF) is important, such as biology [2], food science [3], nanomaterials [4], geochemistry [5], archaeology [6], and environmental science [7]. ...
... For the 3d transition metals, the Kβ n = 2 shake-off satellite is often close in energy to the valence to core Kβ 2,5 , 3d → 1s, forbidden transition [28]. Studies of the Kβ n = 2 satellite 3,4 , no empirical data exist for this transition. A previous result for this transition reported a single energy rather than an eigenvalue spectrum; the two results are within 1 eV of this work's peak energy [77]. ...
Characteristic x-ray spectra offer insight into the structure and composition of atoms and molecules at a fundamental level where discrepancies in asymmetry, peak energy, and shape between theory and experiment motivate investigations. This work calculates highly convergent electron wavefunctions using the multiconfiguration Dirac-Hartree-Fock method and reveals the capability of recreating x-ray spectra from first principles, with eigenvalue convergence of order 0.1 eV and amplitude convergence of order 1–4%. The canonical Kα and Kβ transitions, [1s]→[2p] and [1s]→[2p], respectively, where square brackets denote hole states, are not sufficient to recreate major features present in the data. Shake-off satellites, where the transitions take place in the presence of a secondary nl hole, are necessary to account for observed asymmetries. The probabilities for these shake-off events are determined and used to obtain ab initio satellite intensities. The Auger effect is considered for these satellite intensities through an Auger suppression factor. This work presents the full energy eigenvalue spectrum for several scandium transitions: [1s2] hypersatellites (Kαh and Kβh), the n=2 Kα3,4 and Kβ equivalent satellites, and double shake-off satellites. Calculations are compared with deconvolved experimental data using several fitting models which yield compelling goodness of fit χr2=1.14 for Kα and χr2=1.72 for Kβ. The selected best model is chosen through the statistical F-test and this model is fitted with raw (not deconvolved) experimental data with χr2=0.92 (Kα) and χr2=1.31 (Kβ).
... In contrast, for Ca, the calculated t-value (−1.71654) was close to the critical value, indicating no significant difference between the two methods in detecting Ca. This finding highlights pXRF's reliability and precision in measuring Ca concentrations in plant samples, as it demonstrated comparable results to the highly established ICP-OES technique (Feng, Zhang, and Yu 2021). The capability of pXRF to accurately measure elements like Ca and P has also been documented in previous studies Kalcsits 2016). ...
Understanding nutrient availability and pollution risk in plants is essential for effective environmental and agricultural management. This study evaluates the performance of portable X-ray fluorescence (pXRF) for nutrient analysis in tropical plant samples, comparing it to inductively coupled plasma optical emission spectroscopy (ICP-OES). We analyzed 24 composite samples of cocoa, oil palm, cocoyam, and maize leaves and barks from western Ghana, focusing on K, Ca, Mn, Fe, Cu, Zn, Sr, Cd, Mg, Al, P, S, Ti, Ni, and Co. Our findings revealed K as the most abundant nutrient, with ICP-OES emphasizing the importance of Ca, Mg, and various micronu-trients. Trace elements like Sr and Cd were present at minimal, non-threatening levels. A paired t-test showed no significant differences between pXRF and ICP-OES for key elements such as Ca (−1.71654), Mn (1.12), Fe (1.32), Al (1.71), and Ni (0.735), with all t-values below the critical threshold (t_tab ¼ 1.714), confirming pXRF's effectiveness. Regression analysis indicated strong correlations for Al (r 2 ¼ 0.8185) and P (r 2 ¼ 0.7172), while weaker correlations were observed for Cd (r 2 ¼ 0.0001).Principal component analysis revealed less variability in pXRF data compared to ICP-OES, reinforcing its reliability. ANOVA results showed that organ type significantly influenced elemental concentrations (F ¼ 5.541, p ¼ 0.0203), with K and Ca being the most abundant. Overall, pXRF is a cost-effective tool for nutrient monitoring, though further improvements in sensitivity for certain elements are recommended for broader applications. ARTICLE HISTORY
... Further analyzed by mass spectrometry that detects the type and distribution of heavy metals It offers simultaneous estimation of multiple metals. It is very rapid and sensitive and provides spatial distribution for both elements and isotopes at a microregional level Exhibit isobaric interference and lack of precision Pan et al. [37] X-ray fluorescence The principal is based on the specific X-ray emission spectrum generated by the specimen It measures both quantitative and qualitative metal distribution in plants/ alga single cell, hence suitable for surface analysis of plants as it can predict the mechanism of metal uptake, that is, accumulation or absorption Cannot be used precisely when heavy metal concentrations are below parts per million level, issue of autofluorescence Feng, Zhang, and Peiqiang [38] Electrochemical method Stripping voltammetry Measurement is based on potential, current, or charge that directly correlates concentration of heavy metals The method uses electrodes and is applied for consecutive and qualitative/ quantitative analysis of heavy and transition metals Initially, tooling is costly, and byproducts are harmful to the environment, and high power consumption Okpara et al. [39] 4 BioMed Research International heavy metals in polluted soil, water, and bioaccumulated plants. Molecular biology is also employed to understand heavy metal-induced stress, chemical form, uptake, spatial distribution, translocation, and accumulation in plants [40]. ...
Heavy metals are lethal and hazardous pollutants for the ecosystem owing to their virtues including acute toxicity, prolonged persistence, and bioaccumulation. These contaminants are not only a threat to aquatic/terrestrial biota but also pose serious health issues to humans. Natural and anthropologic processes consistently upsurge heavy metal concentration beyond acceptable limits and mobilization and hence disturb biogeochemical cycles and the food chain, although several conventional strategies including adsorption, chemical precipitation, ion exchange, and membrane separation methods are being employed for the removal of these lethal heavy metals from the ecosystem but failed due to lower efficiency rates and high application charges. The current scenario highly demands advanced biosorption or bioaccumulation processes that slow down heavy metal mobilization within the acceptable limit in the ecosystem. Genetically modified microorganisms (GMMs) with desired features are developed through interdisciplinary participation of genomics, molecular microbiology, and bioinformatics that have more potential to bioremediate heavy metals than the native microbes from polluted ecosystems. The study focuses on different sources of heavy metals, their impact on the ecosystem, and the bioremediation of toxic heavy metals via GMMs.
... While X-ray imaging is commonly used in the medical field, security purposes, and luggage screening [12], its potential in the food and agricultural industry remains is improving [13]. Soft X-ray imaging offers numerous advantages, including no sample preparation, non-destructiveness, costeffectiveness, reliability, rapidity, ease of handling, and high throughput, producing images in just 2 to 3 s [14,15]. Several previous studies have successfully demonstrated the adaptability of X-ray imaging in the horticulture sector, such as detecting internal defects and bitter rot in apples [16,17], internal rot in avocados [18], internal disorders in pears [19], seed spoilage location in mangoes [1]. ...
Alphonso, a renowned mango variety cultivated in India, is commercially valuable for its delightful taste, vibrant saffron color, texture, and prolonged shelf life, attracts global attention. Spongy Tissue (ST) disorder is prevalent in mangoes, especially in the Alphonso variety, leading to spongy and corky texture in the fruit’s pulp. This issue has been identified in as much as 30% of mangoes in a single lot, resulting in the entire lot being rejected during export due to the delayed detection of the disorder. Current mango quality assessment involves destructive cutting, causing fruit damage, leading to significant loss. Limited physical checks don’t ensure overall batch quality. By considering above challenges present study demonstrates on use of X-ray imaging technique for detecting internal quality of mango non-destructively along with machine learning algorithms for automatic binary classification (Non spongy vs. Spongy). For evaluation 648 original X-ray images of mangoes were captured and augmented to 3888 images using different augmentation techniques. For automated classification purposes deep learning (DL) models were used. For automated classification, DL models were employed and fine-tuned through grid search hyperparameter optimization within a 5-fold cross-validation framework. Among the DL models, namely CNN, ResNet50, AlexNet, VGG16, and VGG19, they achieved notable overall accuracy rates of 87.27%, 89.18%, 90.21%, 91.75% and 95.82%, respectively, on the test dataset. Significantly, the VGG19 model demonstrated superior performance with highest classification accuracy by TukeyHSD test. DL in X-ray imaging shows promise for detecting internal issues in fruits, enhancing inspection capabilities for diverse purposes, such as identifying diseases or damages.
Graphical Abstract
... X-ray has different absorption rates for materials with different densities, and this difference in absorption rate is reflected in the gray value of X-ray images, which can distinguish bones, soft tissues, and cavities with different densities. In addition, well-designed X-ray systems have been widely used for the identification and classification of various foods [12][13][14]. Due to the lack of a direct correlation between the internal quality and the external appearance of dried abalone, it is necessary to assess its internal structure. Traditional methods for analyzing the internal quality of dried abalone rely on histological analysis, combined with experiential judgment. ...
As living standards have improved, consumer demand for high-quality dried abalone has increased. Traditional abalone grading is achieved through slice analysis (sampling analysis) combined with human experience. However, this method has several issues, including non-uniform grading standards, low detection accuracy, inconsistency between internal and external quality, and high loss rate. Therefore, we propose a deep-learning-aided approach leveraging X-ray images that can achieve efficient and non-destructive internal quality grading of dried abalone. To the best of our knowledge, this is the first work to use X-ray to image the internal structure of dried abalone. The work was divided into three phases. First, a database of X-ray images of dried abalone was constructed, containing 644 samples, and the relationship between the X-ray images and the internal quality of the dried abalone was analyzed. Second, the database was augmented by image rotation, image mirroring, and noise superposition. Subsequently, a model selection evaluation process was carried out. The evaluation results showed that, in a comparison with models such as VGG-16, MobileNet (Version 1.0), AlexNet, and Xception, VGG-19 demonstrated the best performance in the quality grading of dried abalone. Finally, a modified VGG-19 network based on the CBAM was proposed to classify the quality of dried abalone. The results show that the proposed quality grading method for dried abalone was effective, achieving a score of 95.14%, and outperformed the competitors, i.e., VGG-19 alone and VGG-19 with the squeeze-and-excitation block (SE) attention mechanism.
... Samples were analyzed to study the chemical characteristics of chicken litter waste. The chemical characteristics analyzed were proximate composition (moisture, volatile matter, ash, and fixed carbon) [20] pH, electrical conductivity (EC) with a pH meter, cation exchange capacity (CEC) by leaching NH4OAc pH 7, and nutrient composition (Walkey and black method; Kjeldahl method [21] and XRF analysis) [22]. Scanning electron microscope/energy dispersive X-ray spectroscopy (SEM/EDX) is employed for examining the microstructures [23], and Fourier Transform Infra-Red Spectrophotometer (FT-IR) was obtained to check the presence of different functional groups [24]. ...
Waste from the broiler and layer farming industry with a closed-house system continues to increase without optimizing waste utilization and harms the environment. Potential chicken litter waste from the chicken farming industry in West Sumatra is 5 tons per harvest (40 days) from a chicken livestock capacity of 100,000 chickens. This research aims to assess the potential and utilization and study the biochemistry of chicken manure waste in closed-house systems as biosorbents and fertilizers through amelioration technology. Closed-house chicken coop bedding waste (CHCCW) in the form of sawdust has functional groups such as carboxyl that can absorb cations because it can increase the negative charge in the soil so that it can be utilized by plants. In addition, the CHCCW can also absorb cations (pollutants). Chemical characteristics from the analysis results prove the ability of the CHCCW. Chicken litter waste has chemical characteristics that have the potential as a biosorbent and are valid as fertilizer, which has a proximate composition (moisture 4.26%; volatile matter 74.20%; ash 6.78% and fixed carbon 14.76%); pH (pH H2O 8.37 and pH PZC 7.37); electrical conductivity (EC) >2 dS m-1 and cation exchange capacity (CEC) 182.67 Cmol(+)kg-1. The nutrient composition of chicken manure waste in closed-house systems has macro nutrients (6.88% C; 0.06% N; 5.89% P; 34.89% K; 36.28% Ca; 5.76% S) and micronutrients (2.49% Fe; 1.39% Mn; 1.22% Zn; 1.01% Cu; and 5.15% Cl). Chicken manure waste in closed-house systems also has functional groups such as O-H, N-H, C-H, C-OH, C=C, C=O, C-O-C, Si-O, and O-CH3, which play an active role in the absorption of pollutants and nutrients in the soil.
... While X-ray imaging is commonly used in the medical field, for component inspection in industries, security purposes, and luggage screening (Kotwaliwale et al., 2014), its potential in the food and agricultural industry remains improving (Azadbakht et al., 2019). Soft X-ray imaging offers numerous advantages, including no sample preparation, non-destructiveness, cost-effectiveness, reliability, rapidity, ease of handling, and high throughput, producing images in just 2-3 s (Du et al., 2019;Feng et al., 2020). Several previous studies have successfully demonstrated the adaptability of X-ray imaging in the horticulture sector, such as detecting internal defects and bitter rot in apples (Si & Sankaran, 2016;Van Dael et al., 2019), internal rot in avocados (Matsui et al., 2022), internal disorders in pears ( Van de Looverbosch et al., 2021), seed spoilage location in mangoes (Ansah et al., 2023), and granulation in citrus fruits (Nayak et al., 2022). ...
The globally renowned Alphonso mango is esteemed for its exceptional flavor, fragrance, texture, and extended shelf life. However, it faces a substantial challenge with spongy tissue (ST) disorder, affecting up to 30% of a single lot. This issue leads to the rejection of entire batches during export due to delayed detection, causing significant produce loss. Additionally, the current destructive assessment method is inadequate, as physically inspecting only a few mangoes within a batch does not ensure overall quality, emphasizing the need for a non‐destructive approach. To address these challenges, this study proposes a non‐destructive approach utilizing X‐ray imaging to identify ST in Alphonso mangoes, employing machine learning (ML) for binary classification. We captured and augmented 216 X‐ray images, utilizing various augmentation techniques. K‐means clustering effectively distinguished healthy and ST‐affected areas in mango fruits. For automated classification, ML models were fine‐tuned through grid search hyperparameter optimization within a 5‐fold cross‐validation framework. The CNN model achieved impressive accuracies of 99.20% and 96.82% at threshold values of .5 and .95, respectively, on the test dataset, while the SVM model attained overall accuracy rates of 95.23% and 87.35% for the same thresholds. Our study demonstrates the potential of machine learning in X‐ray imaging for detecting internal fruit issues, improving inspection for disease and damage identification, and enhancing quality control across the food industry. Practical implications include the implementation of non‐destructive inspection methods to reduce produce loss and ensure consistent quality in mango lots. Future research could focus on validating the model's efficacy with external datasets, evaluating its robustness in detecting various internal irregularities, and exploring advancements in X‐ray imaging technology for broader applications in agriculture.
Practical applications
The suggested non‐destructive approach provides a practical solution for quality control, especially in export scenarios. The versatility of the ML‐powered X‐ray imaging technique to examine internal irregularities in various fruits beyond mangoes broadens its potential application in the fruit industry for sorting and grading purposes. This innovation contributes to heightened consumer satisfaction, providing a cost‐effective and scalable solution for widespread implementation. In summary, the findings of the study show promise for revolutionizing mango quality control, particularly for the esteemed Alphonso variety, and propelling advancements in fruit inspection methodologies across the industry.
... In absence of specific provisions for spices and herbs in the European Union (EU) regulatory framework, the assessment of authenticity and purity needs to be aligned with relevant ISO standards. To evaluate these ISO criteria, several analytical methods with complementary outputs are implemented, ranging from high-performance liquid chromatography coupled to mass spectrometry for non-authorised synthetic dyes and chemical markers (such as piperine for pepper, Sing et al., 2022;ISO 11027:1993) to X-ray fluorescence spectroscopy for elements detection such as heavy metals (Feng et al., 2021) and DNA-based analyses to highlight the presence of undeclared species (Gao et al., 2023;Hoffman et al., 2021). Hence, several sophisticated frauds have been evidenced with multistep workflows (Garber et al., 2016;Ordoudi et al., 2017;Xu et al., 2023). ...
Consumers and companies associated with food or pharmaceuticals rely on spices and herbs in various forms. Their intricate supply chains, elevated prices, and low-volume production render them vulnerable to fraudulent practices. However, comprehensive methodologies to detect adulterants remain scarce, impeding national control laboratories from enforcing European and national legislation. In this study, we present quantitative real-time PCR (qPCR) methods designed to identify the top five adulterants of each of six commonly consumed spices and herbs: paprika/chili, turmeric, saffron, cumin, oregano and black pepper. The specificity of each method was confirmed by qPCR analysis of a large collection of relevant plant species. Each authentic sample was combined with its respective top five adulterants as identified in the European Union-wide coordinated control plan on herbs and spices in 2021 or in the existing literature. These binary mixtures were used to evaluate the method's performance with respect to sensitivity, linearity and trueness at four levels of adulterants concentration. Detection was also investigated in multi-adulterated samples. These SYBR™ Green-based qPCR methods enable the specific detection of adulterants, and their sensitivity allows for the distinction between inadvertent contamination and deliberate adulteration. Altogether, these methods contribute to safeguard the authenticity of these high-value commodities.
... Although several elemental analysis techniques are available (such as Inductively Coupled Plasma (ICP) spectroscopy and its coupled variations or Flame Atomic Absorption Spectrometry (FAAS)), the untargeted nature of total X-ray fluorescence (TXRF) spectroscopy has been pointed out as a high-throughput analytical tool to efficiently analyse food products' elemental composition and provide the necessary large datasets for chemometric approaches to trace the product's geographical origin while simultaneously providing precise food nutritional values (Kelly et al., 2005;Lim et al., 2021;Rajapaksha et al., 2017). Additionally, this is a low-cost technique when compared to other available analytical techniques, requiring minimal sample preparation, being fast and sensitive, and allowing multi-elemental quantitative profiling (Feng et al., 2021). ...
Market demand, climate change and soil degradation force producers to maintain the productivity and quality of high-market-value products, such as Protected Geographical Indication (PGI) fruits. “Maçã de Alcobaça” apples produced in the central-western part of Portugal, namely the variety Royal Gala, one of the PGI varieties with higher demand, are among those with higher requirements in terms of fertilization to maintain the high productivity demanded by the market. In the present work, three different soil NPK fertilization schemes were applied to experimental orchards within the PGI area (1 x mineral NPK proposed for integrated production, an intermediate strategy that included organic granular amendment and 2 x mineral NPK), and the elemental profiles of the apple pulps were analysed and compared. Some mineral elements improved their concentration in the apple pulps with fertilization due to interactions of these elements with the fertilizer components (namely, nitrogen, potassium and phosphorus) or to potential changes in the bioavailability of the elements in the soil due to fertilization application. From a nutritional perspective, enhancing the mineral profile of apple pulps can be achieved by applying 1 x NPK fertilization. Consuming an average of 2 fruits daily (160g each) would then help meet a higher percentage of the daily requirements for most essential elements crucial for human nutrition. Also, noteworthy to mention, that none of the tested fertilization practices led to a reduction in the nutritional quality of the fruits analysed when compared to the 1 x NPK condition. The present work also had the objective of evaluating if these fertilization practices and the mineral changes induced would have implications for the PGI authenticity elemental signatures previously developed. Using Partial least squares-discriminant analysis (PLS-DA) models calibrated with PGI and non-PGI (from North Portugal and Italy) samples and feeding these models with elemental profile data of fruits collected from fertilized orchards as blind samples, it was possible to observe that all samples from the fertilization trials were correctly classified as PGI samples. This reinforces the edaphic characteristics of the cultivation area's prevalent role over the effect of fertilization practices or physiological trait changes, in shaping the elemental signature of the fruits. This was found to be mostly due to the high influence of geologically linked elements (such as Rb, Pb and Y) in the discrimination of the sample provenance. This allows us to confirm the suitability of the elemental traceability models for “Maçã de Alcobaça” PGI authenticity validation, ensuring its provenance and nutritional characteristics to the consumers and maintaining its market value even if fertilization practices are applied to fight less favourable cultivation conditions.
... PCA is one of the most commonly used chemometric tools used in combination with EDXRF to discriminate sample types (according to their origin, quality, species, variety, etc) in food science and nutrition (Feng et al., 2021;Čepo et al., 2022). In the present study, element concentrations (K, Ca, Mn, Fe, Cu, Zn, Rb and Sr) determined using empirical EDXRF method This preprint research paper has not been peer reviewed. ...
... PCA is one of the most commonly used chemometric tools in combination with EDXRF to discriminate sample types (according to their origin, quality, species, variety, etc) in food science and nutrition [25,26]. In the present study, element concentrations (K, Ca, Mn, Fe, Cu, Zn, Rb and Sr) determined using the empirical EDXRF method were used as variables. ...
... PCA is one of the most commonly used chemometric tools used in combination with EDXRF to discriminate sample types (according to their origin, quality, species, variety, etc) in food science and nutrition (Feng et al., 2021;Čepo et al., 2022). In the present study, element concentrations (K, Ca, Mn, Fe, Cu, Zn, Rb and Sr) determined using empirical EDXRF method This preprint research paper has not been peer reviewed. ...
... Simultaneous measurement of chromium and manganese has been taken by different detection methods such as radio isotopic method (Dudała et al. 2005), Graphite furnace atomic absorption spectroscopy (Lin and Huang 2001), atomic absorption spectrophotometry (Kazi et al. 2008), and inductively coupled plasma mass spectrometry (Chevallier et al. 2015). One of the fast methods, without destroying the sample and with the least sample preparation, is the X-ray fluorescence method (Feng et al. 2021). The X-ray fluorescence device has been used in several cases to measure chromium and manganese one by one or simultaneously (Fleming and Ware 2017;Morris 1968;Bahadir et al. 2016). ...
A rapid and simple method was optimized through experimental design and validated for the separation of chromium and manganese with magnetic sorbent of Fe3O4@Ag and 2-(2-thiazolylazo)-p-cresol ligand from the effluent of a steel factory. The adsorbed metals on the magnetic sorbent were simply separated using a magnet and collected on filter paper to measure with an X-ray fluorescence device. The infrared spectroscopy, ultraviolet–visible spectroscopy, field emission scanning electron microscopy, and wavelength-dispersive X-ray spectroscopy were used to characterize and follow the steps of the constructed sorbent synthesis. The surface response methodology was used to achieve better figures of merit and more accuracy. Optimal values for the three effective parameters of the response pH, sorbent amount, and sample solution volume were obtained to be 6.0, 4.0 mg, and 50.0 mL, respectively. Under optimum conditions, the detection limits of 0.5 µg mL−1 and 1.6 µg mL−1 for chromium and manganese ions were achieved, respectively. The acceptable linear range of 2.0–100.0 and 5.0–100.0 µg mL−1 was obtained for chromium and manganese, respectively. To show the efficiency of the method, the heavy metals of chromium (20.0 µg mL−1) and manganese (30.0 µg mL−1) were measured with a high accuracy (n = 3), and the recovery was 98% and the relative standard deviation was 2.1% in the real samples of the effluent of a steel factory.
... Moreover, the X-ray fluorescence technique (XRFT) was recently used in food and agricultural research, such as evaluating food safety inspection, plant diseases, and Carelated disorders in fruits and vegetables. More exhaustive work is needed to increase the application of XRFT widely and successfully [90,91] for quality evaluation of fruits and vegetables. Some other potential future investigations of fluorescence imaging applications for product quality assessment could be machine-learning-based fluorescence lifetime microscopy imaging [92], low-cost-smartphone-based fluorescence system [93], chlorophyll fluorescence imaging [94], and fluorescence spectroscopy [95]. ...
Currently, optical imaging techniques are extensively employed to automatically sort agricultural products based on various quality parameters such as size, shape, color, ripeness, sugar content, and acidity. This methodological review article examined different machine vision techniques, with a specific focus on exploring the potential of fluorescence imaging for non-destructive assessment of agricultural product quality attributes. The article discussed the concepts and methodology of fluorescence, providing a comprehensive understanding of fluorescence spectroscopy and offering a logical approach to determine the optimal wavelength for constructing an optimized fluorescence imaging system. Furthermore, the article showcased the application of fluorescence imaging in detecting peel defects in a diverse range of citrus as an example of this imaging modality. Additionally, the article outlined potential areas for future investigation into fluorescence imaging applications for the quality assessment of agricultural products.
... This gave the percentage of the individual element among all detected elements. After the analysis of each sample, mean values were calculated from 4 replicates per sample (Paltridge et al. 2012;Feng et al. 2020;Sharma et al. 2015). ...
Salinity and a lack of proper irrigation water in recent years have seriously affected the maintenance of crops, including strawberries. In this study, an experiment consisted of 2 treatment factors. The first factor, anti-stress compounds, occurred at four levels (control, hydrogen sulfide (H 2 S) as 200 μM sodium-hydrosulfide (NaHS) by foliar application once a week, selenium (Se) as 1 mg L −1 sodium selenate (Na 2 SeO 4) in the nutrient solution, and H 2 S+Se). The second factor, salinity, occurred at two levels (0 and 40 mM NaCl). Each treatment group had 4 replications. Rooted strawberry plants (cv. "Parus") grew in plastic pots filled with cocopeat/perlite (v/v 1:1). The H 2 S, Se, and H 2 S+Se treatments alleviated the adverse effects of salinity on leaf area by 67, 63, and 73%, respectively, and on yield by 66, 63, and 82%, respectively. The highest inhibition percentage of free radicals (84%), anthocyanin content, and the highest concentrations of potassium and calcium in fruits were observed in plants of the H 2 S+Se treatment group. The Se treatment increased the concentration of selenium from 2.67 to 3.02 mg kg −1 dry weight of fruit. Thus, under salinity stress, the combined application of the two anti-stress compounds (H 2 S and Se) strengthened the antioxidant system and adjusted the balance of nutrient absorption, thereby reducing the adverse effects of salinity stress on growth parameters and increasing the strawberry yield, compared to the control and separate application of each of these two compounds.
... However, the equipment used in the past was very expensive and large, and required highly specialized operators. Nowadays, thanks to portable spectroscopes, the XRF technique is used for the analysis of soils [37], minerals and other geological samples [38,39], in archaeology for the chemical characterization of excavations [40,41], and for the analysis of food: fruits, vegetables, grains or dairy products [42,43]. The method is also used for the rapid determination of heavy metal concentrations in contaminated water, which may in the future significantly support wastewater neutralization processes in industry [32]. ...
... XFI is a powerful tool used to measure the distribution and concentrations of macro and micro elements (P, S, Ca, K, Mn, Fe, Cu, and Zn) in food and feeds with a high spatial resolution and without damaging the samples (Deng et al., 2022;Feng et al., 2021;Wetzel et al., 1998). When the X-rays interacting with the inner shell electrons of atoms have sufficient energy, they can remove these electrons from their shells creating core holes. ...
It is important to know the mineral distribution in cereal grains for nutritional improvement or genetic biofortification. Distributions and intensities of micro-elements (Mn, Fe, Cu, and Zn) and macro-elements (P, S, K and Ca) in Arborg oat were investigated using synchrotron-based on X-ray fluorescence imaging (XFI). Arborg oat provided by the Crop Development Center (CDC, Aaron Beattie) of the University of Saskatchewan for 2D X-ray fluorescence scans were measured at the BioXAS-Imaging beamline at the Canadian Light Source. The results show that the Ca and Mn were mainly localized in the aleurone layer and scutellum. P, K, Fe, Cu, and Zn were mainly accumulated in the aleurone layer and embryo. Particularly the intensities of P, K, Cu, and Zn in the scutellum were higher compared to other areas. S was also distributed in each tissue and its abundance in the sub-aleurone was the highest. In addition, the intensities of S and Cu were highest in the nucellar projection of the crease region. All these elements were also found in the pericarp but they were at lower levels than other tissues. Overall, the details of these experimental results can provide important information for micronutrient biofortification and processing strategies on oat through elemental mapping in Arborg oat.
... Chicken is among the most common sources of proteins consumed worldwide. X-ray technology development for better detection of cartilage and bones in chickens can save resources and time, and improve food safety and consumer protection (Feng et al., 2021;Kotwaliwale et al., 2014). The detection of contaminants in real-time is ripe for future exploration. ...
The burden of foodborne diseases and their associated illness/death is a global concern. Hazard analysis and critical control points (HACCP) and food safety/quality management are employed to combat this problem. With the existing and emerging food safety/quality management concerns, this study aims to evaluate the traditional and modern/novel approach to improving HACCP, food safety, and quality management in food and agricultural systems. The modern innovations in food safety management were integrated into improving the traditional HACCP system, including its principles, applications, steps, plans, standards, etc., as well as food safety factors and management, for improved safety/quality in food, agricultural, and pharmaceutical industries. The study identified many factors responsible for food contamination, including chemical contaminants, such as allergens, histamine, cyanogenic glycosides, mycotoxins, toxic elements, etc., biological contaminants, such as Campylobacter, Brucella, viruses, Escherichia coli, prions, Staphylococcus aureus, Listeria monocytogenes, protozoa, parasitic pathogens, etc., and physical contaminants, such as bone, glass, metal, personal effects, plastic, stones, wood, etc. The results of this study present descriptive preliminary HACCP steps, HACCP principles, safe food handling procedures, ISO 22000, Water quality management, food labelling, etc., with recent modern developments and innovations to ensure food safety and quality management. The study also identified modern/novel technologies for HACCP and food safety management, including light technologies, artificial intelligence (AI), novel freezing (isochoric freezing), automation, and software for easy detection and control of contaminants. With all these understanding and development, the domestic, food, agricultural, and pharmaceutical industries can be well position to ensure safety and quality of products.
... X-ray spectral qualitative and quantitative analyses are based on the dependence of the intensities of the spectrum lines of certain elements on the content in the samples under analysis. The interaction of primary and secondary radiation with the sample leads to dependence of the analytical line intensity both on the content of the element to be determined and on the chemical composition of the sample to be analyzed (Feng et al., 2021). This method has its several prefers like as minimal needs for the sample preparation, no destruction of the sample, it has a high spatial resolution, and the possibility of multiple measurements of the elements (Célia et al., 2022). ...
... 1-10 At farm or food production line, online control should involve a few hundred analyses per day; thus compact hand-held instruments are required. Nowadays, hand-held instruments based on X-ray uorescence [11][12][13][14] and laser-induced breakdown spectroscopy (LIBS) [15][16][17][18][19] techniques are good candidates for the online control of heavy elements in plant or food materials. However, LIBS has few benets compared to XRF: faster analysis (few seconds vs. few minutes); X-ray emission is dangerous for the operator; and remote vs. contact measurements. ...
The impact of the laser spot dimensions on the laser-induced breakdown spectroscopy (LIBS) analysis of heterogeneous samples was studied in detail. The study was stimulated by comparing the analytical performance of three LIBS instrument types that have potential utilization at different stages of agricultural material control: a hand-held analyzer, laboratory LIBS system, and an online industrial system installed on a production line (conveyer belt, etc.). Laser spot diameters (120 to 1100 μm) with the same averaged energy density were utilized for heterogeneous sample analysis of materials with particle sizes from 20 to 300 μm; thus, every spot could probe from one to a few hundred particles. Few-hundred-point LIBS maps were generated to construct calibration curves with different numbers of averaged spots (from 4 to 400). The analytical capabilities were compared in terms of the linearity and accuracy of determination. For large spot sampling, a better linearity and better accuracy of zinc determination in soybean grist were achieved compared to the small spot sampling. It was demonstrated for the first time that a few dozen LIBS spots should be probed to achieve a representative analysis in the case of heterogeneous material LIBS analysis (such as plants or its products) while only a few spots are generally sampled in the published LIBS studies to date.
... Considering elemental profiling, total X-ray fluorescence (TXRF) spectroscopy has been pointed out as a high-throughput non-targeted analytical tool to efficiently depict the foodstuff products' elemental composition, tracing the product's geographical origin whilst simultaneously, providing accurate food nutritional values (Kelly et al., 2005;Lim et al., 2021;Rajapaksha et al., 2017). Moreover, TXRF requires minimal sample preparation, being a low-cost (reduced reagents and gas costs), fast and sensible technique for multi-elemental quantitative profiling (Feng et al., 2021). ...
Food fraud associated with intentional mislabelling of non-Protected Geographical Indication (PGI) is a concern for consumers. “Maçã de Alcobaça” (Alcobaça apple) is one of the oldest Portuguese PGI products, characteristic of the main apple-growing regions in the country, being of utmost importance to develop traceability and authenticity tools to depict the PGI certification status of these products. Pulp multielement signatures were able to discriminate with moderate accuracy (65.7 %) different Royal Gala clones, grown within the same cultivation area. Moreover, Variable Importance in Projection Partial Least-Squares Discriminant Analysis (VIP-PLS-DA) allowed to depict the Royal Gala samples from different PGI producers with 70.0 % accuracy. Apple PGI cultivars were also discriminated accurately (82.0 %). Expanding the approach to non-PGI production areas, several cultivars could be distinguished, according to their provenance with high accuracy, namely Starking (100.0 % accuracy), Granny Smith (100.0 % accuracy), Fuji (100.0 % accuracy), Royal Gala (86.7 % accuracy) and Reineta (90.3 % accuracy). The PGI fruits microelement nutritional traits highlighted their higher nutritional value, an important trait for food fraud reduction, inform the consumer of the product authenticity, and provide insights on the nutritional value of these high-value market products.
... Micro-spectroscopy, µX-ray fluorescence (µXRF) tomography, where X-ray induce the reemission of a X-ray fluorescent radiation from the sample, is a promising method which provides information about the chemistry of 2D (Schlüter et al., 2022) or 3D samples. Its use is very rare in 3D, in particular because improvements still have to be made to circumvent problems of fluorescence attenuation in soils (Feng et al., 2021;Hapca et al., 2015;Roose et al., 2016). Fluorescent light can be absorbed by the sample, in particular in the case of thick samples, thus attenuating the fluorescent signal. ...
The soil microhabitat is a heterogeneous and complex environment where local variations can modulate phenomena observed at the plot scale. Most of the current methods used to describe soil functioning are bulk soil analyses which do not account for fine-scale spatial variability and cannot fully account for the processes that occur under the influence of the 3D organisation of soil. A good representation of spatial heterogeneities is necessary for the parametrisation of new models, which aim to represent pore-scale processes that affect microbial activity. The visualization of soil at the scale of the microhabitat can be used to extract descriptors and reveal the nature of the relationships between the fine-scale organisation of soil's constituent parts and soil functioning.
However, soil imaging techniques tend to be under-used, possibly due to a lack of awareness of the methods or due to a lack of access to the relevant instruments. In recent years, new methods have been developed, and continuously improved, offering new possibilities to decipher and describe soil physical, chemical and biological features of the soil microhabitat in evermore exquisite detail.
This review is structured into several sections in which we consider first imaging methods that are useful for describing the distribution of microorganisms and identify them, second the methods for characterising the physical organisation and the chemical attributes of the microhabitat, including soil organic matter and, finally, methods for visualising in situ information on the activities of microorganisms are described. Special attention is given to the preparation steps that are required for the proper use of the methods, either alone or in combination.
RNA N6-methyladenosine (m6A) modification plays a crucial role in the DNA damage response, while the detailed mechanisms remain to be explored. In this study, we report the involvement of the m6A demethylase ALKBH5 in X-ray-induced DNA damage response. Depletion of ALKBH5 reduces X-ray-induced DNA damage, induces G2/M phase arrest and reduces cell apoptosis. RNA sequencing and m6A sequencing analysis reveal that ALKBH5 removes m6A modifications from its target mRNAs and suppresses their expression. A subset of mRNAs encoding cyclin dependent kinase inhibitors, such as CDKN1A and CDKN2B, show increased stability and expression upon ALKBH5 knockdown. Subsequently, the upregulation of CDKN1A and CDKN2B contributes to G2/M phase arrest to facilitate DNA repair. Our findings unveil the epigenetic regulation of cell cycle checkpoint by ALKBH5 in X-ray-induced DNA damage, offering potential targets for DNA damage-based therapy for cancers.
In recent years, advances in X-ray optics and detectors have enabled the commercialization of laboratory μXRF spectrometers with spot sizes of ~3 to 30 μm that are suitable for routine imaging of element localization, which was previously only available with scanning electron microscopy (SEM-EDS). This new technique opens a variety of new μXRF applications in the food and agricultural sciences, which have the potential to provide researchers with valuable data that can enhance food safety, improve product consistency, and refine our understanding of the mechanisms of elemental uptake and homeostasis in agricultural crops. This month’s column takes a more detailed look at some of those application areas.
The aim of this study is to compare analytical methods (energy dispersive X-ray fluorescence spectrometry (ED-XRF) and inductively coupled plasma (ICP) for determining the geographical origin of dry red peppers. The concentration of inorganic elements was set as a variable, and a geographical origin discrimination analysis was performed using canonical discriminant analysis (CDA) as a chemometrics tool. CDA analysis shows potential as a food analysis tool and is the most commonly used analytical method for determining geographical origin by analyzing inorganic elements. ED-XRF analysis achieved 96.25% accuracy in determining of the geographical origin of dry red peppers, while inductively coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectrometry (ICP-MS) afforded 98.75% accuracy. Through these results, we aim to compare the pros and cons of the ED-XRF and ICP analysis to utilize a more accurate and efficient approach to determine the geographical origin of agricultural products.
Micro X-ray Fluorescence (μXRF) is a technology for non-destructive detection of elements with high resolution. Currently, the μXRF imaging system cannot scan with a fixed distance and incident angle, which highly affects the measurement consistency of curved objects. To solve this problem, we developed a novel Three-dimensional (3D) μXRF imaging system based on a robotic arm and a depth camera. In our system, the depth camera is used to capture both the coordinates and normal vectors of the contour of the object, while the μXRF spectrometer is installed on the six-axis robotic arm to flexibly scan the curved surface according to the contour. Compared to the existing systems, the proposed 3D μXRF imaging system eliminates the interference to the counts caused by the changes in the X-ray incident angle and distance, which improves the 3D imaging quality of curved surfaces. The highest resolution of the system can be controlled to within 50μm, and the single-point acquisition time can be as short as milliseconds. The alloy sample scanning experiment quantitatively demonstrated the fluctuation of the detector counts is only 0.62% within 18mm of the alloy sample surface, while the fluctuations of the other two scanning methods are 3.79% and 9.42%. The oil painting experiment validated the accuracy of the imaging system in element identification and imaging, by comparing it with ground truth. Teapot and cylinder experiments are performed to demonstrate the system’s capability for high-precision and high-resolution 3D imaging of objects in any orientation.
As an integral part of daily dietary intake, the market demand for fruits and vegetables is continuously growing. However, traditional methods for assessing the quality of fruits and vegetables are prone to subjective influences, destructive to samples, and fail to comprehensively reflect internal quality, thereby resulting in various shortcomings in ensuring food safety and quality control. Over the past few decades, imaging technologies have rapidly evolved and been widely employed in nondestructive detection of fruit and vegetable quality. This paper offers a thorough overview of recent advancements in nondestructive imaging technologies for assessing the quality of fruits and vegetables, including hyperspectral imaging (HSI), fluorescence imaging (FI), magnetic resonance imaging (MRI), thermal imaging (TI), terahertz imaging, X-ray imaging (XRI), ultrasonic imaging, and microwave imaging (MWI). The principles and applications of these imaging techniques in nondestructive testing are summarized. The challenges and future trends of these technologies are discussed.
The study focuses on the impact of supplementing corn flour with soybean flour and different cooking methods on sensory evaluation. Mineral content and composition of corn-based products Corn and soybeans are nutritious staples, with soybean flour enriching food products with protein and essential amino acids. Investigating these factors, cooking techniques influence the sensory attributes and nutritional quality of food. The study aims to optimize the sensory and nutritional qualities of corn-based products supplemented with soybean flour. In a study examining the effects of supplementing corn flour with varying levels of soybean cake and cooking, it was found that supplementing with 3, 5, and 7% soybean flour led to a slight increase in protein content. Cooking further increased the protein content while total mineral contents (K, Ca, Mn, Fe, Cu, and Pb) decreased. Moisture content decreased compared to the control, but ash fiber, oil, carbohydrate, and total energy levels varied. Corn flour porridge supplemented with 7% soybean flour was preferred by panellists for colour, aroma, taste, and overall acceptability compared to other supplemented flour porridges. These results illustrate how adding soybean flour to corn-based goods can improve their sensory qualities and nutritional value. The total nutritional profile can be enhanced and the protein level raised by adding soybean flour; furthermore, the finished product's sensory qualities can be improved to increase consumer appeal. Soybean is an essential ingredient in functional foods as it is a beneficial source of protein. 45% contain most of the essential amino acids, vitamins, and minerals. Soybean is also rich in lysine and tryptophan, two of the essential amino acids that are limited in cereals. Soybean protein is also rich in Ca, P, and vitamins A, B, C, and D. Soybean is also a useful source of polyunsaturated fatty acids such as linoleic acid, which accounts for approximately 50 percent of the total fat content and is beneficial for health.
Interactive technologies that shape the traditional human-food experiences are being explored under the emerging field of Human-Food Interaction (HFI). A key challenge in developing HFI technologies is the digital sensing of food, beverages, and their ingredients, commonly known as digital food sensing. Digital food sensing involves recognizing different food and beverages and their internal attributes, such as volume and ingredients (e.g., salt and sugar content). Contemporary research on interactive food applications, such as dietary assessment, primarily employs Computer Vision (CV) techniques to identify food; however, they are ineffective when 1) identifying food’s internal attributes, 2) discriminating visually similar food and beverages, and 3) seamlessly integrating with people’s natural interactions while consuming food. Thus, this paper reviews potential food and beverage sensing technologies that can facilitate novel Human-Food Interfaces, primarily focusing on non-disruptive sensing techniques to analyze food and beverages during consumption. First, we review ten different digital food sensing techniques and their applications in four categories. Then, we discuss three main aspects to consider when adopting these food-sensing techniques for human-food interface designs. Finally, we suggest the future research requirements in digital food sensing methodologies, followed by potential applications of digital food sensing in future developments of Human-Food Interfaces.
The study focuses on the impact of supplementing corn flour with soybean flour and different cooking methods on sensory evaluation. Mineral content and composition of corn-based products Corn and soybeans are nutritious staples, with soybean flour enriching food products with protein and essential amino acids. Investigating these factors, cooking techniques influence the sensory attributes and nutritional quality of food. The study aims to optimize the sensory and nutritional qualities of corn-based products supplemented with soybean flour. In a study examining the effects of supplementing corn flour with varying levels of soybean cake and cooking, it was found that supplementing with 3, 5, and 7% soybean flour led to a slight increase in protein content. Cooking further increased the protein content while total mineral contents (K, Ca, Mn, Fe, Cu, and Pb) decreased. Moisture content decreased compared to the control, but ash fiber, oil, carbohydrate, and total energy levels varied. Corn flour porridge supplemented with 7% soybean flour was preferred by panellists for colour, aroma, taste, and overall acceptability compared to other supplemented flour porridges. These results illustrate how adding soybean flour to corn-based goods can improve their sensory qualities and nutritional value. The total nutritional profile can be enhanced and the protein level raised by adding soybean flour; furthermore, the finished product's sensory qualities can be improved to increase consumer appeal. Soybean is an essential ingredient in functional foods as it is a beneficial source of protein. 45% contain most of the essential amino acids, vitamins, and minerals. Soybean is also rich in lysine and tryptophan, two of the essential amino acids that are limited in cereals. Soybean protein is also rich in Ca, P, and vitamins A, B, C, and D. Soybean is also a useful source of polyunsaturated fatty acids such as linoleic acid, which accounts for approximately 50 percent of the total fat content and is beneficial for health.
X-ray fluorescence spectroscopy (XRF) is an analytical technique employed to determine the elemental composition of diverse materials. Due to its nondestructive nature and direct analysis that requires little or no sample preparation, it has been particularly useful for investigating the mineral composition of plants and soil. However, commercially available XRF benchtop equipment often restricts this type of experiment in plant science due to the volume of the sample chamber and the source−detector geometry. To overcome this problem, we developed an XRF setup that prioritizes in vivo-based experiments. The equipment is equipped with a 4 W Ag X-ray tube and a silicon drift detector. The detection limits are comparable to those of commercial instruments and suitable for evaluating plant tissues. Finally, a case study using tomato plants as a model species and rubidium (Rb +) and strontium (Sr 2+) as tracers for potassium (K +) and calcium (Ca 2+), respectively, demonstrated their feasibility for long-term in vivo analysis. Therefore, the present XRF system stands out as a viable and cost-effective tool for assessing the absorption and transport of minerals in plant tissues probed by time-resolved in vivo X-ray spectroscopy.
Heavy metal (HM)-induced stress can lead to the enrichment of HMs in plants thereby threatening people’s lives and health via the food chain. For this reason, there is an urgent need for some reliable and practical techniques to detect and analyze the absorption, distribution, accumulation, chemical form, and transport of HMs in plants for reducing or regulating HM content. Not only does it help to explore the mechanism of plant HM response, but it also holds significant importance for cultivating plants with low levels of HMs. Even though this field has garnered significant attention recently, only minority researchers have systematically summarized the different methods of analysis. This paper outlines the detection and analysis techniques applied in recent years for determining HM concentration in plants, such as inductively coupled plasma mass spectrometry (ICP-MS), atomic absorption spectrometry (AAS), atomic fluorescence spectrometry (AFS), X-ray absorption spectroscopy (XAS), X-ray fluorescence spectrometry (XRF), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), non-invasive micro-test technology (NMT) and omics and molecular biology approaches. They can detect the chemical forms, spatial distribution, uptake and transport of HMs in plants. For this paper, the principles behind these techniques are clarified, their advantages and disadvantages are highlighted, their applications are explored, and guidance for selecting the appropriate methods to study HMs in plants is provided for later research. It is also expected to promote the innovation and development of HM-detection technologies and offer ideas for future research concerning HM accumulation in plants.
To meet the growing demand for food quality and safety, there is a pressing need for fast and visible techniques to monitor the food crop and product production processing, and to understand the chemical changes that occur during these processes. Herein, the fundamental principles, instruments, and characteristics of three major laser-based imaging techniques (LBITs), namely, laser-induced breakdown spectroscopy, Raman spectroscopy, and laser ablation-inductively coupled plasma-mass spectrometry, are introduced. Additionally, the advances, challenges, and prospects for the application of LBITs in food crops and products are discussed. In recent years, LBITs have played a crucial role in mapping primary metabolites, secondary metabolites, nanoparticles, toxic metals, and mineral elements in food crops, as well as visualizing food adulteration, composition changes, pesticide residue, microbial contamination, and elements in food products. However, LBITs are still facing challenges in achieving accurate and sensitive quantification of compositions due to the complex sample matrix and minimal laser sampling quantity. Thus, further research is required to develop comprehensive data processing strategies and signal enhancement methods. With the continued development of imaging methods and equipment, LBITs have the potential to further explore chemical distribution mechanisms and ensure the safety and quality of food crops and products.
This book aims to inform readers about the latest trends in environment-friendly extraction techniques in food analysis. Fourteen edited chapters cover relevant topics. These topics include a primer green food analysis and extraction, environment-friendly solvents, (such as deep eutectic solvents, ionic liquids, and supramolecular solvents), and different extraction techniques.
Key Features
- Includes topics for basic and advanced readers
- Covers a wide range of green solvents for food analysis
- Emphasizes modern extraction techniques (including supercritical fluid extraction, the gas expanded liquid extraction, pressurized liquid extraction, microwave-assisted extraction, pulse electric field extraction)
- Provides notes on selection of solvents
- Includes references for every chapter
The blend of fundamental and applied information makes this an ideal reference for food chemistry students and research scholars. It also serves as a guide for professional experts working in food analysis and sustainability roles.
In this paper, a thiacalix[4]arene complex [Zn2(TIT4A)L2]·4DMF·2CH3OH (H2L = 4,4'-oxybisbenzoic acid) (Zn-TIT4A-L) was synthesized by a solvothermal method. The composites were prepared by combining Zn-TIT4A-L with reduced graphene oxide (RGO), mesoporous carbon (MC), and multi-walled carbon nanotubes (MWCNTs), respectively. Three representative composites are Zn-TIT4A-L@RGO(1:1), Zn-TIT4A-L@MC(1:2), and Zn-TIT4A-L@MWCNT(1:2). X-ray diffraction and scanning electron microscopy characterized their structures and morphologies. The results showed that three composites were successfully prepared, and the crystals of the complex remained in the composites. The electrochemical properties of the composites were characterized by electrochemical impedance spectroscopy and cyclic voltammetry. The results indicated that they had good electrocatalytic activity and conductivity. Among them, Zn-TIT4A-L@RGO(1:1) had the best performance and was used for the quantitative detection of flutamide (FTA). The linear range of detection is 0.1-200 μM, and the limit of detection is 0.015 μM. At the same time, the sensor also had good reproducibility, anti-interference, and stability. The sensor was also used for the detection of FTA in lake water, human urine, and serum with a satisfactory recovery rate. The possible mechanism of electrochemical detection of FTA was also discussed.
Kimchi has been designated as one of the world's five healthiest foods, and it is a traditional Korean fermented food. The purpose of this study was to investigate whether the origin of Kimchi can be discriminated against by using inorganic elements to develop a more accurate method. The OPLS-DA showed that the R2 and Q2 values were 0.908 and 0.81, a high-quality model. We selected 24 elements (133Cs, 238U, 88Sr, K, 157Gd, Na, Mg, 139La, P, 141Pr, 72Ge, 146Nd, 147Sm, 153Eu, 55Mn, 165Ho, 163Dy, 166Er, Fe, 172Yb, 169Tm, 185Re, 175Lu, and 118Sn) with VIP 1 or higher in the OPLS-DA model. In ROC, the selected elements had an accuracy of 100%. The heatmap confirmed the contents of rare earth elements (REEs) in Korean and Chinese Kimchi, the accuracy of distinguishing classification in CDA is 100%. Such results will help to distinguish the origin of agricultural products through inorganic analysis.
In this study, a rapid screening method for elemental impurities in pharmaceutical products has been established by portable energy dispersive X-ray fluorescence (EDXRF) spectroscopy combined with the efficient fundamental parameter method. The proposed method has been used for the screening of 22 elemental impurities (i.e., Cd, Pb, As, Hg, Co, V, Ni, Tl, Au, Pd, Ir, Os, Rh, Ru, Se, Ag, Pt, Sb, Mo, Cu, Sn, and Cr) in the International Conference on Harmonization (ICH) Q3D guideline. The verification of results could meet the acceptance criteria for accuracy, precision and linearity in the United States Pharmacopoeia 〈233〉. On the other hand, the limit of quantitation of the proposed EDXRF method for the screening of 22 elemental impurities in pharmaceutical products could meet the concentration limits of each element at 10 g maximum daily intake based on the established permitted daily exposure to oral drugs in the ICH Q3D guideline. Our findings open up new possibilities in the rapid screening of pharmaceutical products for the detection of elemental impurities by EDXRF, which can be expected to provide a novel, nondestructive, high-throughput, portable, and sensitive platform for the process control of elemental impurities to ensure the quality and safety of drugs.
With the development of modern industry, it can be said that from industrial production to the basic necessities of life, plastic products can be seen everywhere. What follows is the disposal of plastic waste. How to deal with plastic waste correctly is closely related to people’s health and the earth’s environment. In this paper, laser-induced breakdown spectroscopy is applied for the online in situ detection of plastic and its combustion smoke. According to the spectrum obtained, the main components of plastics are Ca, Mg, Na, K, C, H and O. In the spectrum of smoke, the characteristic peaks of the elements C, H, O and N are observed. In addition, the online detection of heavy metal pollution is simulated. Finally, principal component analysis and error back propagation artificial neural networks were applied for the identification of different plastics and their combustion smoke, and the identification accuracy reaches 92.73% and 77.42% respectively. All the results indicate that laser-induced breakdown spectroscopy technology has great potential in the identification of similar objects and the monitoring of air pollutants.
There is an urgent need for the accurate analysis of heavy metal contamination in the field of ecology and environmental sciences, especially in the case of trace heavy metals, such as cadmium. Using doubly curved crystals (DCC) to achieve the monochromatic X-ray excitation of the sample to be measured and a silicon drift detector (SDD) to collect the fluorescence of the sample elements, combined with an algorithm analysis of the fundamental parameters (FP), the monochromatic energy-dispersive X-ray fluorescence (MED-XRF) system significantly improved the detection limits of the target elements. The detection limits, precision, and accuracy of the MED-XRF acquisition for 20 elements, including cadmium, lead, and arsenic, were evaluated and compared with the Determination of Inorganic Elements in Soil and Sediment Wavelength-Dispersive X-ray Fluorescence Spectrometry report and tested on the actual samples. The test results showed that the detection limit of the inorganic elements in soil and sediment determined by MED-XRF was mostly better than the industry standard, especially the detection limit of Cd, which was 0.04 mg/kg. The accuracy and correctness fully met the requirements for daily laboratory testing and, as a quality control tool, the actual sample testing and laboratory ICP-MS results were consistent. The research conducted in this project constituted a useful attempt to expand and improve the analytical methods for inorganic elements in soil and sediment, showing that MED-XRF is superior to conventional ED-XRF and WD-XRF and is the current new method of analysis for a low content of Cd in soil. MED-XRF offers a very important contribution to research on soil census, conservation, the rational use of agricultural land, and soil restoration and improvement, and provides strong support for field testing.
Over the last two decades, advances in the design, miniaturization, and analytical capabilities of portable X-ray fluorescence (pXRF) instrumentation have led to its rapid and widespread adoption in a remarkably diverse range of applications in research and industrial fields. The impetus for this volume was that, as pXRF continues to grow into mainstream use, analysts should be increasingly empowered with the right information to safely and effectively employ pXRF as part of their analytical toolkit. This volume provides introductory and advanced-level users alike with readings on topics ranging from basic principles of pXRF and qualitative and quantitative approaches, through to machine learning and artificial intelligence for enhanced applications. It also includes fundamental guidance on calibrations, the mathematics of calculating uncertainties, and an extensive reference index of all elements and their interactions with X-rays. Contributing authors have provided a wealth of information and case studies in industry-specific chapters. These sections delve into detail on current standard practices in industry and research, including examples from agricultural and geo-exploration sectors, research in art and archaeology, and metals industrial and regulatory applications.
As pXRF continues to grow in use in industrial and academic settings, it is essential that practitioners continue to learn, share, and implement informed and effective use of this technique. This volume serves as an accessible guidebook and go-to reference manual for new and experienced users in pXRF to achieve this goal.
O homem é frequentemente responsável por causar danos ao ambiente, notadamente, no solo e na água. Quando se realiza uma atividade agronômica, deve-se estar ciente de que ela pode trazer impactos negativos ao ambiente, sendo necessárias medidas de prevenção, monitoramento, controle e/ou recuperação. O solo é responsável pela ciclagem de elementos químicos, haja vista que sequestra carbono, regula o ciclo hidrológico e é um suporte da biodiversidade da fauna e da flora, entre outras funções ambientais. O recurso natural solo está em constante interação com a litosfera, hidrosfera, biosfera e atmosfera. Em decorrência destas relações, a degradação do solo é um dos componentes de risco para a manutenção da vida no planeta. Os processos de degradação, entretanto, precisam ser diagnosticados a tempo de serem interrompidos e recuperados. Deste modo, em sistemas integrados de produção, as técnicas inovadoras de monitoramento e de diagnóstico da degradação e conservação do solo e da água são de grande importância para a sustentabilidade dos solos agrícolas. No mundo, a agricultura se tornou cada vez mais especializada, com benefícios voltados à produção e acessibilidade de alimentos. Ao mesmo tempo, a produção agrícola especializada e a monocultura têm levantado preocupações com relação ao bem-estar animal, à degradação ambiental e perda da biodiversidade. Uma alternativa à agricultura convencional é a integração de culturas e animais no contexto agropecuário. A agricultura integrada de lavouras, florestas e pecuária pode melhorar à qualidade do solo, aumentar a produção sustentável, produzir uma diversidade maior de alimentos, melhorando a eficiência do uso da terra (FAO, 2010). Capítulo 9 266 No entanto, a agricultura e a agropecuária nunca estão isentas de desafios, haja vista que os produtores frequentemente necessitam de informações especializadas em agricultura, criação de animais, diversidade genética, infraestrutura de processamento de produtos de origem animal etc. Estes aspectos foram abordados por Hilimire (2011) em sua revisão sobre sistemas integrados de produção nos EUA. Estudos conduzidos por Franzluebbers et al. (2014) sobre os impactos agronômicos e ambientais dos sistemas integrados agrícolas e de pastagens na América do Norte e do Sul, indicaram que a agricultura se tornou cada vez mais especializada em resposta às pressões políticas, reguladoras, sociológicas e econômicas, buscando atender às demandas de um mercado cada vez maior do setor de processamento de alimentos e fibras. No entanto, há uma preocupação crescente com sistemas agrícolas especializados, devido aos impactos potencialmente negativos ao ambiente, à redução da qualidade do solo, à eutrofização dos corpos d’água, ao aumento das emissões de gases de efeito estufa e às perdas de solo, água, nutrientes e carbono orgânico. Os mesmos autores realizaram uma revisão sobre os sistemas integrados de produção na América do Norte e do Sul e realçaram os seguintes aspectos: (1) substanciais ganhos na produtividade de culturas agrícolas quando cultivadas após pastagens; (2) aumento do teor de matéria orgânica do solo relacionado às pastagens perenes; (3) melhoria na infiltração de água no solo com consequente redução na perda de solo e água; e (4) ganhos sinérgicos, entre os sistemas de cultivo e pecuária, no tocante à produtividade sustentável e ao ambiente. Trabalhos conduzidos, envolvendo sistemas integrados de produção agropecuária sustentável sob sequeiro e irrigação por Blanco-Canqui et al. (2016) nos EUA, apontaram efeito benéfico dos resíduos de milho (Zea mays L.) nas pastagens subsequentes e na redução das perdas de solo. Na China, estudos desenvolvidos por Dai et al. (2018) indicaram que a expansão das áreas de plantios agrícolas, em todo o mundo, tem levantado preocupações sobre sua capacidade de oferecer suporte a vários serviços ecossistêmicos. Foram avaliados cinco tipos de ecossistemas e serviços (produção de madeira, provisão de água, armazenamento de carbono, conservação do solo e retenção de água) fornecidos por florestas plantadas e naturais. Os resultados mostraram que os benefícios gerais dos serviços ecossistêmicos foram mais altos em cultivos mistos, seguidos por plantações de coníferas e de folhas largas. Além disso, a proteção das florestas naturais foi realçada. Estudos semelhantes conduzidos por Saad et al. (2018), utilizando os modelos Universal Soil Loss Equation (USLE) e InVEST, evidenciaram que trabalhos futuros devem considerar as estratégias de restauração da vegetação nas áreas de recarga de água, os sistemas de manejo conservacionista e a biodiversidade na agropecuária. O monitoramento, diagnóstico, dimensionamento e a simulação de cenários dos processos de degradação do solo são fundamentais na gestão agropecuária moderna. O Capítulo 9 267 principal enfoque nesta linha, refere-se à melhoria da eficiência desses procedimentos, aprimorando sua acurácia e agilidade, através de conceitos e tecnologias inovadores, notadamente nos sistemas integrados de produção agrícola. Ao longo dos anos, a versatilidade, a acurácia e a facilidade de acesso oferecidas pelos softwares e pelos sistemas gerenciados por eles, têm conduzido a uma aceitação crescente pela comunidade científica e técnica. Novos sistemas baseados em sensores próximos, robótica, modelagem, inteligência artificial, transmissão de dados via internet e outras tecnologias têm se mostrado capazes de reduzir a dependência atual da agricultura à produtos químicos, melhorar sua sustentabilidade, reduzir o impacto ambiental e otimizar seu gerenciamento (Saiz-Rubio e Rovina-Más, 2020). Para isso, os profissionais envolvidos devem trabalhar em grupos de pesquisa multidisciplinares e acompanhar a rápida evolução destas tecnologias (Lopes e Steidle Neto, 2011). Portanto, pretende-se neste capítulo abordar o potencial das inovações tecnológicas de monitoramento e diagnóstico da degradação e conservação do solo e da água nos sistemas integrados de produção agropecuária.
Foliar analysis is very important for the nutritional management of crops and as a supplemental parameter for soil fertilizer recommendation. The elemental composition of plants is traditionally obtained by laboratory-based methods after acid digestion of ground and sieved leaf samples. This analysis is time-consuming and generates toxic waste. By comparison, portable X-ray fluorescence (pXRF) spectrometry is a promising technology for rapid characterization of plants, eliminating such constraints. This worked aimed to assess the pXRF performance for elemental quantification of leaf samples from important Brazilian crops. For that, 614 samples from 28 plant species were collected across different regions of Brazil. Ground and sieved samples were analyzed after acid digestion (AD), followed by quantification via inductively coupled plasma optical emission spectroscopy (ICP-OES) to determine the concentration of macronutrients (P, K, Ca, Mg, and S) and micronutrients (Fe, Zn, Mn, and Cu). The same plant nutrients were directly analyzed on ground leaf samples via pXRF. Four certified reference materials (CRMs) for plants were used for quality assurance control. Except for Mg, a very strong correlation was observed between pXRF and AD for all plant-nutrients and crops. The relationship between methods was nutrient- and crop-dependent. In particular, eucalyptus displayed optimal correlations for all elements, except for Mg. Opposite to eucalyptus, sugarcane showed the worst correlations for all the evaluated elements, except for S, which had a very strong correlation coefficient. Results demonstrate that for many crops, pXRF can reasonably quantify the concentration of macro- and micronutrients on ground and sieved leaf samples. Undoubtedly, this will contribute to enhance crop management strategies concomitant with increasing food quality and food security.
Elemental analysis using energy-dispersive X-ray fluorescence on extra virgin olive oils and seed oils revealed the presence of two major concentration related clusters, one containing elements of pedological origin, whilst the other consisted of heavy metals. Seed oils were found to contain a higher concentration of titanium when compared to extra virgin olive oils, whilst extra virgin olive oils derived from the Maltese Islands had a significantly higher concentration of barium and phosphorus on using the Kruskal–Wallis one-way ANOVA (p-value < 0.05 for both elements). Application of stepwise linear canonical discriminate analysis proved to be highly superior to PCA, as it was able to distinguish between seed oils from extra virgin olive oils and distinguish between foreign and locally produced extra virgin olive oils.
Portable XRF is a rapid, mobile, high throughput, and potentially cost effective instrumental analytical technique capable of elemental assessment. It is widely used for environmental assessment of soils in a variety of contexts such as agriculture and pollution both in-situ and ex-situ, to varying levels of success. Portable XRF performance for soil analysis is often validated against wet chemistry techniques but a range of factors may give rise to elementally dependent disparities affecting accuracy and precision assessments. These include heterogeneity, analysis times, instrument stability during analyses, protective thin films, incident X-rays, sample thickness, sample width, analyte interferences, detector resolution, power source fluctuations and instrumental drift. Light elements comprising water and organic matter (i.e. carbon, oxygen) also negatively affect measurements due to X-ray scattering and attenuation. The often-overlooked phenomenon of variability in both soil organic matter and water can also affect soil density (e.g. shrink-swell clays) and thus sample critical thickness which in turn affects the effective volume of sample analyzed. Compounding this, for elements having lower characteristic fluorescence energy, effective volumes of analyses are lower and thus measurements may not be representative of the whole sample. Understanding the effects and interplay between determined elemental concentrations and soil organic matter, water, and critical thickness together with the subtlety of theoretical effective volumes of analyses will help analysts mitigate potential problems and assess the applicability, advantages and limitations of PXRF for a given site. We demonstrate that with careful consideration of these factors and a systematic approach to analysis which we summarize and present, PXRF can provide highly accurate results.
Seed germination is the essential first step in crop establishment, and can be severely affected by salinity stress which can inhibit essential metabolic processes during the germination process. Salt stress during seed germination can trigger lipid-dependent signalling cascades that activate plant adaptation processes, lead to changes in membrane fluidity to help resist the stress, and cause secondary metabolite responses due to increased oxidative stress. In germinating barley (Hordeum vulgare), knowledge of the changes in spatial distribution of lipids and other small molecules at a cellular level in response to salt stress is limited. In this study, mass spectrometry imaging (MSI), liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QToF-MS), inductively coupled plasma mass spectrometry (ICP-MS), and X-ray fluorescence (XRF) were used to determine the spatial distribution of metabolites, lipids and a range of elements, such as K⁺ and Na⁺, in seeds of two barley genotypes with contrasting germination phenology (Australian barley varieties Mundah and Keel). We detected and tentatively identified more than 200 lipid species belonging to seven major lipid classes (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, prenol lipids, sterol lipids, and polyketides) that differed in their spatial distribution based on genotype (Mundah or Keel), time post-imbibition (0 to 72 h), or treatment (control or salt). We found a tentative flavonoid was discriminant in post-imbibed Mundah embryos under saline conditions, and a delayed flavonoid response in Keel relative to Mundah. We further employed MSI-MS/MS and LC-QToF-MS/MS to explore the identity of the discriminant flavonoid and study the temporal pattern in five additional barley genotypes. ICP-MS was used to quantify the elemental composition of both Mundah and Keel seeds, showing a significant increase in Na⁺ in salt treated samples. Spatial mapping of elements using µ-XRF localized the elements within the seeds. This study integrates data obtained from three mass spectrometry platforms together with µ-XRF to yield information on the localization of lipids, metabolites and elements improving our understanding of the germination process under salt stress at a molecular level.
This research was conducted to evaluate the utility and reliability of X‐ray fluorescence (XRF) spectroscopy to analyze macro‐ (K and Ca) and micronutrients (Mn, Fe, Cu, Zn, and Se) in pea (Pisum sativum L.) seeds. The pea seed samples were ground into flour and pelleted to collect the XRF spectra. Seventy‐three pea seed samples were selected to cover the expected concentration ranges for each element to develop calibration curves by correlating the XRF results with atomic absorption spectroscopy (AAS). The XRF results were validated by a systematic comparison of data obtained from AAS on a set of 80 additional and independent pea seed samples. Element concentrations were also predicted using the fundamental parameter approach collectively for 153 samples. For all the calibration curves, the R² value was >0.8, except for K (0.54). For Mn, Fe, Cu, Zn, and Se, the XRF predictions were similar to AAS measurements at a 95% confidence level. Similar results were obtained with the fundamental parameter approach except for Fe for which significant bias of ∼6 mg kg⁻¹ was calculated. Except for K, R value for all the validation curves was >0.85. Thus, the results obtained using XRF and the fundamental parameter approach were statistically not different from the AAS method. This study demonstrated that the XRF technique is a fast and reliable, nondestructive, and noninvasive analytical tool for mineral analysis, particularly for transition metals, does not produce waste, and requires no chemical reagents.
Biofortification of crops with selenium (Se) is an effective strategy to increase the consumption of this micronutrient. Inductively coupled plasma mass spectrometry (ICP-MS) is one of the most used techniques in quantifying Se. However, due to some disadvantages (high cost, long analysis time, and being destructive), there is a need for new alternatives to Se quantification. This study aimed at establishing instrumental parameters for Se quantification, using two energy-dispersive X-ray fluorescence spectrometry (EDXRF) techniques (benchtop and handheld) in Se-biofortified broccoli seedlings and comparing it with ICP-MS. The results showed that the selection of proper filters for both EDXRF systems was crucial for determining Se and, when compared with ICP-MS, presented similar results for selenium-biofortified broccoli seedling treatments (BS50Se). In addition, the EDXRF techniques presented a Se limit of detection (LOD) at 0.6–0.9 mg kg−1. This study demonstrates that EDXRF systems were successfully applied to concentration measurement of Se in biofortified samples and linked to low cost and shorter analysis time.
Multilevel interactions among nutrients occur in the soil-plant system. Among them, Fe and Zn homeostasis in plants are of great relevance because of their importance for plant and human nutrition. However, the mechanisms underlying the interplay between Fe and Zn in plants are still poorly understood. In order to elucidate how Zn interacts with Fe homeostasis, it is crucial to assess Zn distribution either in the plant tissues or within the cells. In this study, we investigated the subcellular Zn distribution in Fe-deficient leaf cells of cucumber plants by using two different approaches: cellular fractionation coupled with inductively coupled plasma mass spectrometry (ICP/MS) and nanoscopic synchrotron X-ray fluorescence imaging. Fe-deficient leaves showed a strong accumulation of Zn as well as a strong alteration of the organelles’ ultrastructure at the cellular level. The cellular fractionation-ICP/MS approach revealed that Zn accumulates in both chloroplasts and mitochondria of Fe deficient leaves. Nano-XRF imaging revealed Zn accumulation in chloroplast and mitochondrial compartments, with a higher concentration in chloroplasts. Such results show that (i) both approaches are suitable to investigate Zn distribution at the subcellular level and (ii) cellular Fe and Zn interactions take place mainly in the organelles, especially in the chloroplasts.
The present study investigated the role of trichomes in absorption of foliar-applied Zn fertilizers in soybean and tomato. Using synchrotron-based X-ray fluorescence microscopy for in situ analyses of hydrated leaves, we found that upon the foliar-application of ZnSO4, Zn accumulated within 15 min in some non-glandular trichomes of soybean, but not tomato. However, analyses of cross sections of soybean leaves did not show any marked accumulation of Zn in tissues surrounding trichomes. Furthermore, when near-isogenic lines of soybean differing 10-fold in trichome density were used to compare Zn absorption, it was found that foliar Zn absorption was not related to trichome density. Therefore, it is suggested that trichomes are not part of the primary pathway whereby foliar-applied Zn moves across the leaf surface in soybean and tomato. However, this does not preclude trichomes being important in other plant species, as trichomes are known to be highly diverse. We also compared the absorption of Zn when supplied as ZnSO4, with nano- and bulk-ZnO, finding that the absorption of Zn from ZnSO4 was ca. 10-fold higher than from nano- and bulk-ZnO, suggesting that Zn was mainly absorbed as soluble Zn. This study improves our understanding of the absorption of foliar-applied nutrients.
Understanding how seeds obtain and store nutrients is key to developing crops with higher agronomic and nutritional value. We have uncovered unique patterns of micronutrient localization in seeds using synchrotron X-ray fluorescence (SXRF). Although all four members of the Arabidopsis thaliana Mn-CDF family can transport Mn, here we show that only mtp8-2 has an altered Mn distribution pattern in seeds. In an mtp8-2 mutant, Mn no longer accumulates in hypocotyl cortex cells and sub-epidermal cells of the embryonic cotyledons, but rather accumulates with Fe in the cells surrounding the vasculature, a pattern previously shown to be determined by the vacuolar transporter VIT1. We also show that MTP8, unlike the other three Mn-CDF family members, can transport Fe and is responsible for localization of Fe to the same cells that store Mn. When both the VIT1 and MTP8 transporters are non-functional, there is no accumulation of Fe or Mn in specific cell types; rather these elements are distributed amongst all cell types in the seed. Disruption of the putative Fe binding sites in MTP8 resulted in loss of ability to transport Fe but did not affect the ability to transport Mn.
Synchrotron techniques are powerful tools in material and environmental sciences. However, they are currently underutilized in plant research. The Canadian Light Source synchrotron on the University of Saskatchewan campus is the only such facility in Canada, open to academic, government, and industrial clients. This review introduces the potential of synchrotron-based spectroscopic methods and its applications to agriculture and plant sciences. Relative ease of sample preparation, non-destructive analysis, high spatial resolution and multiple response measurements within a single sample are among its advantages. Synchrotron based Fourier transform mid infrared spectromicroscopy, X-ray absorption and fluorescence spectromicroscopy are included in the several approaches discussed. Examples range from evaluating protein secondary structure; non-destructive compositional analysis of leaf epicuticular wax and pollen surface lipids; as well as cell wall composition and nutrient analyses. Synchrotron technology can help to initially identify key spectra related to plant properties for subsequent higher throughput techniques. One example is the adaptation of synchrotron techniques for lower resolution analysis in the field, such as the non-destructive elemental analysis for localization of nutrients in fruit crops using hand held high throughput devices. In addition, interest in creating high throughput systems based on synchrotron technology itself is driving the development of new hardware to meet these larger challenges.
Zinc (Zn) is essential for all life forms, including humans. It is estimated that around two billion people are deficient in their Zn intake. Human dietary Zn intake relies heavily on plants, which in many developing countries consists mainly of cereals. The inner part of cereal grain, the endosperm, is the part that is eaten after milling but contains only a quarter of the total grain Zn. Here we present results demonstrating that endosperm Zn content can be enhanced through expression of a transporter responsible for vacuolar Zn accumulation in cereals. The barley (Hordeum vulgare) vacuolar Zn transporter HvMTP1 was expressed under the control of the endosperm-specific D-hordein promoter. Transformed plants exhibited no significant change in growth but had higher total grain Zn concentration, as measured by ICP-OES, compared to parental controls. Compared with Zn, transformants had smaller increases in concentrations of Cu and Mn but not Fe. Staining grain cross-sections with the Zn-specific stain DTZ revealed a significant enhancement of Zn accumulation in the endosperm of two of three transformed lines, a result confirmed by ICP-OES in the endosperm of dissected grain. Synchrotron X-ray fluorescence analysis of longitudinal grain sections demonstrated a redistribution of grain Zn from aleurone to endosperm. We argue that this proof-of-principle study provides the basis of a strategy for biofortification of cereal endosperm with Zn. This article is protected by copyright. All rights reserved.
Calcium and potassium are essential for cell signaling, ion homeostasis and cell wall strength in plants. Unlike nutrients such as nitrogen and potassium, calcium is immobile in plants. Localized calcium deficiencies result in agricultural losses; particularly for fleshy horticultural crops in which elemental imbalances in fruit contribute to the development of physiological disorders such as bitter pit in apple and cork spot in pear. Currently, elemental analysis of plant tissue is destructive, time consuming and costly. This is a limitation for nutrition studies related to calcium in plants. Handheld portable x-ray fluorescence (XRF) can be used to non-destructively measure elemental concentrations. The main objective was to test if handheld XRF can be used for semi-quantitative calcium and potassium analysis of in-tact apple and pear. Semi-quantitative measurements for individual fruit were compared to results obtained from traditional lab analysis. Here, we observed significant correlations between handheld XRF measurements of calcium and potassium and concentrations determined using MP-AES lab analysis. Pearson correlation coefficients ranged from 0.73 and 0.97. Furthermore, measuring apple and pear using handheld XRF identified spatial variability in calcium and potassium concentrations on the surface of individual fruit. This variability may contribute to the development of localized nutritional imbalances. This highlights the importance of understanding spatial and temporal variability in elemental concentrations in plant tissue. Handheld XRF is a relatively high-throughput approach for measuring calcium and potassium in plant tissue. It can be used in conjunction with traditional lab analysis to better understand spatial and temporal patterns in calcium and potassium uptake and distribution within an organ, plant or across the landscape.
Background and Aims Phosphorus (P) is an essential nutrient for plants but its low availability often necessitates amendments for agronomical issues. Objectives were to determine P spatial distribution and speciation that remain poorly understood in cultivated soils. Methods Aquic Argiudoll soil samples developed on a calcareous loam glacial till were collected from experimental plots submitted to contrasting crop rotations and amendments. Micro-X-ray fluorescence (μ-XRF) maps were collected on undisturbed samples. X-ray absorption near edge structure (XANES) spectra were collected on bulk samples and on fractions thereof, and on points of interests selected from μ-XRF maps. Results were compared with chemical analyses and extraction techniques results. Results Chemical analyses show variations in total and exchangeable P contents depending on the samples but no significant difference is observed in terms of P distribution and speciation. P distribution is dominated by a low-concentration diffuse background with a minor contribution from minute hot spots. P speciation is dominated by phosphate groups bound to clay-humic complexes. No modification of P distribution and speciation is observed close to roots. Conclusions This study evidenced minor effect of cropping and fertilizing practices on P speciation in cultivated soils. Despite analytical challenges, the combined use of μ-XRF and XANES provides relevant information on P speciation in heterogeneous soil media.
Large area mapping of inorganic material in biological samples has suffered severely from prohibitively long acquisition times. With the advent of new detector technology we can now generate statistically relevant information for studying cell populations, inter-variability and bioinorganic chemistry in large specimen. We have been implementing ultrafast synchrotron-based XRF mapping afforded by the MAIA detector for large area mapping of biological material. For example, a 2.5 million pixel map can be acquired in 3 hours, compared to a typical synchrotron XRF set-up needing over 1 month of uninterrupted beamtime. Of particular focus to us is the fate of metals and nanoparticles in cells, 3D tissue models and animal tissues. The large area scanning has for the first time provided statistically significant information on sufficiently large numbers of cells to provide data on intercellular variability in uptake of nanoparticles. Techniques such as flow cytometry generally require analysis of thousands of cells for statistically meaningful comparison, due to the large degree of variability. Large area XRF now gives comparable information in a quantifiable manner. Furthermore, we can now image localised deposition of nanoparticles in tissues that would be highly improbable to `find' by typical XRF imaging. In addition, the ultra fast nature also makes it viable to conduct 3D XRF tomography over large dimensions.
This technology avails new opportunities in biomonitoring and understanding metal and nanoparticle fate ex-vivo. Following from this is extension to molecular imaging through specific anti-body targeted nanoparticles to label specific tissues and monitor cellular process or biological consequence.
Organic waste from the food processing industry constitutes suitable substrate for anaerobic digestion. The chemical composition of digester feedstock, the availability of nutrients for microorganisms responsible for the anaerobic decomposition of organic compounds and the substrate's toxicity for bacteria have to be controlled in plant material for biogas production. The chemical composition of biomass determines biogas yield and the quality of digestate used as fertilizer. The objective of this study was to analyze the chemical composition and toxicity of food wastes by atomic absorption spectrometry (AAS). The content of heavy and light metals was determined in selected plant wastes, including brewer's spent grain, apple pomace, strawberry pomace, carrot pomace, orange and grapefruit peel, beetroot and potato peel, potato pulp, rapeseed cake, walnut and hazelnut shells. The analyzed wastes were characterized by varied content of Pb, Cd, Cu, Zn, Cr, Ni, Na, K, Mg and Ca. The results of this study can be used to optimize the composition of feedstock for biogas plants.
Inorganic arsenic is a carcinogen, and its ingestion through foods such as rice presents a significant risk to human health. Plants chemically reduce arsenate to arsenite. Using genome-wide association (GWA) mapping of loci controlling natural variation in arsenic accumulation in Arabidopsis thaliana allowed us to identify the arsenate reductase required for this reduction, which we named High Arsenic Content 1 (HAC1). Complementation verified the identity of HAC1, and expression in Escherichia coli lacking a functional arsenate reductase confirmed the arsenate reductase activity of HAC1. The HAC1 protein accumulates in the epidermis, the outer cell layer of the root, and also in the pericycle cells surrounding the central vascular tissue. Plants lacking HAC1 lose their ability to efflux arsenite from roots, leading to both increased transport of arsenic into the central vascular tissue and on into the shoot. HAC1 therefore functions to reduce arsenate to arsenite in the outer cell layer of the root, facilitating efflux of arsenic as arsenite back into the soil to limit both its accumulation in the root and transport to the shoot. Arsenate reduction by HAC1 in the pericycle may play a role in limiting arsenic loading into the xylem. Loss of HAC1-encoded arsenic reduction leads to a significant increase in arsenic accumulation in shoots, causing an increased sensitivity to arsenate toxicity. We also confirmed the previous observation that the ACR2 arsenate reductase in A. thaliana plays no detectable role in arsenic metabolism. Furthermore, ACR2 does not interact epistatically with HAC1, since arsenic metabolism in the acr2 hac1 double mutant is disrupted in an identical manner to that described for the hac1 single mutant. Our identification of HAC1 and its associated natural variation provides an important new resource for the development of low arsenic-containing food such as rice.
Oxalate-producing plants accumulate calcium oxalate crystals (CaOx(c) ) in the range of 3-80%(w/w) of their dry weight, reducing calcium (Ca) bioavailability. The calcium oxalate deficient 5 (cod5) mutant of Medicago truncatula has been previously shown to contain similar Ca, but lower oxalate and CaOx(c) concentrations than wild type (WT) plants. We imaged the Ca distribution in WT and cod5 leaflets via synchrotron X-ray fluorescence mapping (SXRF). We observed a contrast in the Ca distribution between cod5 and WT leaflets, manifested as an abundance of Ca in the interveinal areas and a lack of Ca along the secondary veins in cod5, the opposite of WT. X-ray microdiffraction (μXRD) of M. truncatula leaves confirmed crystalline CaOx(c) (whewellite; CaC2 O4 •H2 O) was present in WT only, in cells sheathing the secondary veins. Together with μXRD, microbeam Ca K-edge X-ray absorption near-edge structure spectroscopy (μXANES) indicated that among the forms of CaOx - namely crystalline or amorphous - only amorphous CaOx was present in cod5. These results demonstrate that deletion of COD5 changes both Ca localization and the form of CaOx within leaflets. This article is protected by copyright. All rights reserved.
Determining the speciation of selenium in vivo is crucial to understanding the biological activity of this essential element, which is a popular dietary supplement due to its anti-cancer properties. Hyphenated techniques that combine separation and detection methods are traditionally and effectively used in selenium speciation analysis, but require extensive sample preparation that may affect speciation. Synchrotron-based X-ray absorption and fluorescence techniques offer an alternative approach to selenium speciation analysis that requires minimal sample preparation. We present a brief summary of some key HPLC-ICP-MS and ESI-MS/MS studies of the speciation of selenium in cells and rat tissues. We review the results of a top-down approach to selenium speciation in human lung cancer cells that aims to link the speciation and distribution of selenium to its biological activity using a combination of X-ray absorption spectroscopy (XAS) and X-ray fluorescence microscopy (XFM). The results of this approach highlight the distinct fates of selenomethionine, methylselenocysteine and selenite in terms of their speciation and distribution within cells: organic selenium metabolites were widely distributed throughout the cells, whereas inorganic selenium metabolites were compartmentalized and associated with copper. New data from the XFM mapping of electrophoretically-separated cell lysates show the distribution of selenium in the proteins of selenomethionine-treated cells. Future applications of this top-down approach are discussed.
The periodic application of copper-based fungicides (Bourdeaux mixture) to vineyards of the Mediterranean region has generated an important pollution source that in some cases requires a quick intervention due to the high bioavailable copper content measured. Despite some vineyards were abandoned 40 years ago, noticeable amounts of Cu and other man-related metals are still nowadays detected in soils. In the present work, the development of a mobility test for the available heavy metal (Cu, Pb, Zn and As) content in soil has been performed using portable X-ray fluorescence (FP-XRF) combined with single leaching test, and was applied to a calcareous soil of a former vineyard area in Catalonia (NE Spain). The combined methodology has provided useful information for fast and detailed risk assessment, in terms of mobility and bioavailability of metals. The anthropogenic contribution was evaluated by means of the Concentration Enrichment Ratios (CER) in soil. The results reflect a clear anthropogenic contribution for Cu, a partial anthropogenic contribution for Pb proceeding from an external pollution source, and a non-significant external contribution for As and Zn. The topsoil concentration ranges for Cu (70–128 mg kg⁻¹) were found to be above the background level and several samples above the regional governmental limits (Generic Reference Levels or GRL values) for soil ecosystem protection and for human health (90 mg kg⁻¹). The present study reveals that the use of FP-XRF equipment constitute a highly valid option for quick decision making during the field location, characterization and quantitative elemental analysis of soil samples for screening of potential pollutants such as heavy metals.
Milk and dairy products are comprised of a complex matrix of components that can interfere with analysis and, as a result, are often not suitable for direct introduction into analytical instruments. Energy‐dispersive X‐ray fluorescence spectrometry (EDXRF) can bypass time‐consuming preparation steps, with potential for rapid, onsite analysis of minerals. In this study, five major milk minerals, sodium, magnesium, potassium, phosphorus and calcium, were quantified in dairy powders, using EDXRF, and the systemic bias of the method was evaluated by Bland–Altman analysis. No significant systemic bias was observed for the quantification of sodium, magnesium, potassium and phosphorus, meaning that EDXRF has potential to be used as a rapid offline analytical technology suitable for the analysis of these minerals in skim milk powders.
Background and aims:
X-ray fluorescence microscopy (XFM) is a powerful technique to elucidate the distribution of elements within plants. However, accumulated radiation exposure during analysis can lead to structural damage and experimental artefacts including elemental redistribution. To date, acceptable dose-limits have not been systematically established for hydrated plant specimens.
Methods:
Here we systematically explore acceptable dose-rate limits for investigating fresh sunflower (Helianthus annuus) leaf and root samples and investigate the time-dose damage in leaves attached to live plants.
Key results:
We find that dose-limits in fresh roots and leaves are comparatively low (4.1 kGy), based on localised disintegration of structures and element-specific redistribution. In contrast, frozen-hydrated samples did not incur any apparent damage even at doses as high as 587 kGy. Furthermore, we find that for living plants subjected to XFM measurement in vivo and grown for a further 9 d before being reimaged with XFM, the leaves display elemental redistribution at doses as low as 0.9 kGy and they continue to develop bleaching and necrosis in the days after exposure.
Conclusions:
The suggested radiation dose limits for studies using XFM to examine plants are important for the increasing number of plant scientists undertaking multidimensional measurements such as tomography and repeated imaging using XFM.
Landfill agricultural soils are common worldwide and pose risks to human health via heavy metals common in such systems. Similarly, anthropogenically deposited organic matrices may lead to methanogenesis in saturated landfill systems. In contrast to traditional methods of landfill agricultural soil characterization, the present study employed a combination of portable X-ray fluorescence (PXRF) spectrometry, NixPRO color sensor, and geostatistical methods to identify hotspots and total spatial area in excess of environmental thresholds in landfill soils of Kolkata, India. Of the 335 points surveyed, Zn, Mn, Cu, and Pb exceeded threshold limits at all sites. Indicator and ordinary kriging were employed to show the spatial variability in elements characterized in this study. Four different pollution indices were calculated and spatially compared: geo-accumulation index (Igeo), enrichment factor (EF), contamination factor (CF) and ecological risk factor (ER). Organic carbon levels ranged from 1.27 to 10.57% with a mean of 4.02%; levels substantively higher than naturally occurring soils of the area indicative of anthropogenic enrichment. The NixPro™ sensor predicted soil OC reasonably well (validation R² = 0.70) without using depth as an auxiliary predictor (a common approach in earlier studies). Summarily, the use of these two portable sensor systems was shown effective at characterizing landfill agricultural soils. Future work should extend the results of this study to in-situ testing and a wider diversity of soil types to corroborate the conclusions presented herein.
A portable energy dispersive X‐ray fluorescence (XRF) spectrometer furnished with an Rh X‐ray tube was evaluated for the determination of macronutrients and micronutrients in soybean leaves (Glycine max L.). XRF instrumental parameters were optimized in a univariate way, and emission intensities were measured for 60 s and under vacuum for macronutrients, and during 180 s, under air, and 305 μm Al/25.4 μm Ti filter, for micronutrients. Fresh and dried leaves were irradiated, and it was possible to identify P, K, Ca, S, Mn, Fe, Cu, and Zn Kα emission lines. For comparative purpose, the samples were also microwave assisted, digested and analyzed by inductively coupled plasma optical emission spectrometry. In general, linear correlations between K, Ca, Mn, Fe, Cu, and Zn concentrations in the tested samples and the corresponding portable XRF (pXRF) intensities were obtained. The linear correlation coefficients (R2) ranged from 0.42 to 0.86. In addition, the detection limits were suitable for plant nutrient diagnosis. It is demonstrated that pXRF is a simple and powerful tool for analysis of plant materials.
This study explored the toxicity of triclosan in the presence of TiO2 P25 to the green alga Eremosphaera viridis in Lake Erie. Multiple physicochemical endpoints were conducted to perform a comprehensive analysis of the toxic effects of individual and combined pollutants. Fourier transform infrared spectromicroscopy and synchrotron-based X-ray fluorescence imaging were first documented to be applied to explore the distribution variation of macromolecules and microelements in single algal cells in interactive toxicity studies. The results were different based on different triclosan concentrations and measurement endpoints. Comparing with individual pollutants, the toxicity intensified in lipids, proteins and oxidative stress at 1000 and 4000 µg/L triclosan in the presence of P25. There were increases in dry weight, chlorophyll content, lipids, and catalase content when cells were exposed to P25 and 15.625 µg/L triclosan. The toxicity alleviated when P25 interacted with 62.5 and 250 μg/L triclosan compared with triclosan-only exposure. The reasons could be attributed to the combination of adsorption, biodegradation, and photocatalysis of triclosan by algae and P25, triclosan dispersion by increased biomass, triclosan adherency on algal exudates, and triclosan adsorption site reduction on algae surface owing to P25’s taking-over. This work provides new insights into the interactive toxicity of nanoparticles and personal care products to freshwater photosynthetic organisms. The findings can help with risk evaluation for predicting outcomes of exposure to mixtures, and prioritize further studies on joint toxicity.
Microgreens are an emerging class of vegetables, which have become increasingly important in the agri-food market in recent years, and contain a number of macro- and micro-nutrients. This paper presents a rapid method for the elemental analysis of microgreens based on total reflection X-ray fluorescence (TXRF) spectroscopy, without preliminary sample digestion.
The following elements were detected and quantified simultaneously for six microgreen genotypes, belonging to Asteraceae and Brassicaceae: P, S, K, Ca, Cl, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr. The limit of detection (LOD) varied depending on the element and ranged between 0.1 mg kg⁻¹ for Sr and 42 mg kg⁻¹ for P.
The method was validated using certified standards, and results compared with those obtained using a conventional ICP-AES method requiring sample digestion. The paper also presents the advantages and disadvantages of the two techniques.
While laboratory methods of elemental analysis of soil nutrients are used frequently to support soil studies, the implementation of more portable and cost-efficient methods lingers behind. The portable (handheld) X-ray fluorescence spectrometer (XRF) is one such tool enabling onsite elemental analysis in a straightforward manner. However, in soil studies the use of XRF often remains cumbersome, following the poor performance of the method for low-Z elemental analysis and the complex nature of the soil matrix, introducing background noise. Here, we therefore evaluate how the potential use of a portable XRF for predicting potassium (K), phosphorus (P), magnesium (Mg) and calcium (Ca) can be improved through the analysis of XRF spectral data with the Random Forest (RF) machine learning method. A total of 105 soil samples from a wide range of soils collected from 10 different countries (D.R. Congo, Belgium, Ivory Coast, Italy, The Netherlands, Saudi-Arabia, South Africa, Spain, Switzerland, and Zimbabwe) were scanned using an Oxford XMET8000 XRF spectrometer (Oxford Instruments, UK). Spectral data of the calibration set (n = 74) were pulled in one matrix alongside measured elemental concentrations and subjected to RF analysis. Resulting models were validated using an independent validation set (n = 31). The best RF prediction result was obtained for K followed successively by Ca, Mg and P with coefficient of determination (R 2) values of 0.83, 0.76, 0.69, and 0.47, and root mean squared error of prediction (RMSEP) of 2283.8, 6818.7, 1511.8, and 538.08 mg kg −1 , respectively. The RF modelling procedure provided improved prediction performance compared to the calibration models provided by the manufacturer (R 2 = 0.65, 0.75, 0.65, and 0.22, for K, Ca, Mg and P, respectively). Our results suggest that portable XRF instruments coupled with spectral data analysis by RF allows for rapid and low-cost analysis of soil K and Ca with remarkable accuracy. Still, the lower measurement accuracy for P and Mg suggests further work is needed to test whether the prediction can be improved by better calibration models, and how such approaches can help overcoming instrumental limitations.
Ecological risk assessment of soil is commonly performed by determining heavy metals (HMs) through conventional laboratory analysis, which is cost-, time-and labor-consuming, especially in large-scale agricultural soils. Therefore, appropriate cheaper and faster analytical methods of comparable accuracy are urgently required. In this study, rapid analyses of HMs were performed via Portable X-ray fluorescence (PXRF) spectrometry and arc emission spectrometry (AES) in agricultural soils from a representative greenhouse vegetable area on the east bank of Dianchi Lake in Kunming City, Yunnan Province, southwest of China. Here AES was specifically used as a replacement of PXRF for measuring Cd in soil because the measurement limit of PXRF for Cd is usually higher than the normal content of Cd in agricultural soils. The performances of rapid analysis and conventional laboratory analysis were compared and evaluated, and ecological risk was assessed with the Nemerow composite pollution index for classifying HM contamination grades and Kriging interpolation for mapping spatial variation. Results showed that the PXRF and AES were applicable and accurate with the relative standard deviation (RSD) and the relative percent difference (RPD) for HMs being within 20%. Significant positive correlations were found between the rapid analysis results and conventional laboratory analysis results for both certified reference materials and collected soil samples. The classification of soil HM contamination grades and their spatial patterns were similar between the rapid analysis and laboratory analysis. Overall, results of the rapid analysis were almost identical to those of conventional laboratory analysis. Therefore, rapid HM analysis using PXRF and AES is effective and economic for accurately assessing ecological risk of agricultural soils in greenhouses.
Soil base saturation percentage (BSP) plays an important role in the assessment of soil taxonomic classification and soil fertility. Conventionally, soil BSP measurement methods are fraught with many drawbacks such as being laborious, time consumptive, destructive to the samples, and can lead to the underestimation of true cation exchange capacity (CEC). Recently, proximal sensors such as portable X-ray fluorescence (PXRF) spectrometry have proven to be effective for rapid physicochemical analysis of soils. In this study, we proposed and examined a PXRF-based method to predict BSP using 300 soil samples from the active agricultural lands in six states across the USA; Colorado, California, Minnesota, Nebraska, Oklahoma, and Texas. An Olympus Vanta series PXRF analyzer was employed to measure Mg, Ca, and K for BSP prediction. Results were validated using four different multivariate models [generalized additive model (GAM), multiple linear regression (MLR), random forest (RF), regression tree (RT)] via R 3.5.1. Predictive model performance was assessed via root mean squared error (RMSE), coefficient of determination (R²), residual prediction deviation (RPD), the ratio of performance to interquartile (RPIQ) range, and bias. While predicting BSP from PXRF quantified elements, models exhibited R², RMSE (%), and RPDs as follows: GAM = 0.58, 9.0, 1.6; MLR = 0.45, 10.4, 1.4; RF = 0.62, 8.7, 1.6; RT = 0.68, 7.9, 1.8, respectively. Soil cation exchange capacity was also predicted using a similar approach, with similar and moderate predictive performance; GAM produced R², RMSE (cmolc kg⁻¹), and RPD of 0.69, 5.6, 1.8, respectively, relative to laboratory data. This study showed that the PXRF elements can be used to predict BSP with fair accuracy for the range of agricultural soils examined. As such, further study and enhancement of the approach outlined herein on a wider array of soils is warranted.
A simple and rapid method for the determination of ash content by Energy Dispersive X-Ray Fluorescence (ED-XRF) was established and validated for milk-based powders. ED-XRF determination can interestingly replace classical gravimetric methods by reducing the analytical time from several hours to three minutes only. Indeed the results obtained show that ED-XRF gives statistically comparable results to classical methods (furnace and thermo-gravimetric analyzer). The relative expanded uncertainty of the ED-XRF method was found to be <10%, which is acceptable.
Using ED-XRF technique for ash content determination on top of elemental determination analyses allows to reduce delays and costs.
Understanding the distribution of elements within plant tissues is important across a range of fields in plant science. In this review, we examine synchrotron-based x-ray fluorescence microscopy (XFM) as an elemental imaging technique in plant sciences, considering both its historical and current uses as well as discussing emerging approaches. XFM offers several unique capabilities of interest to plant scientists, including in vivo analyses at room temperature and pressure, good detection limits (approximately 1-100 mg kg-1), and excellent resolution (down to 50 nm). This has permitted its use in a range of studies, including for functional characterization in molecular biology, examining the distribution of nutrients in food products, understanding the movement of foliar fertilizers, investigating the behavior of engineered nanoparticles, elucidating the toxic effects of metal(loid)s in agronomic plant species, and studying the unique properties of hyperaccumulating plants. We anticipate that continuing technological advances at XFM beamlines also will provide new opportunities moving into the future, such as for high-throughput screening in molecular biology, the use of exotic metal tags for protein localization, and enabling time-resolved, in vivo analyses of living plants. By examining current and potential future applications, we hope to encourage further XFM studies in plant sciences by highlighting the versatility of this approach.
A small mineral fraction substantially determines the nutrition value and quality of milk. The X-ray fluorescence spectrometry (XRF) is an expanding method in the field of elemental analysis of milk. Different configurations of XRF spectrometers are commercially available, and they are known as providing cheap and fast analyses of minerals and some trace elements with the accuracy and reproducibility required for food products. This research review particularly concerns the XRF instrumentation, sample preparation, calibration and quantification procedures. The practical examples of using XRF techniques for determination of minerals and trace elements in milk samples are also demonstrated.
Elemental concentrations in vegetation are of critical importance, whether establishing plant essential element concentrations (toxicity vs. deficiency) or investigating deleterious elements (e.g., heavy metals) differentially extracted from the soil by plants. Traditionally, elemental analysis of vegetation has been facilitated by acid digestion followed by quantification via inductively coupled plasma (ICP) or atomic absorption (AA) spectroscopy. Previous studies have utilized portable X-ray fluorescence (PXRF) spectroscopy to quantify elements in soils, but few have evaluated the vegetation. In this study, a PXRF spectrometer was employed to scan 228 organic material samples (thatch, deciduous leaves, grasses, tree bark, and herbaceous plants) from smelter-impacted areas of Romania, as well as National Institute of Standards and Technology (NIST) certified reference materials, to demonstrate the application of PXRF for elemental determination in vegetation. Samples were scanned in three conditions: as received from the field (moist), oven dry (70 °C), and dried and powdered to pass a 2 mm sieve. Performance metrics of PXRF models relative to ICP atomic emission spectroscopy were developed to asses optimal scanning conditions. Thatch and bark samples showed the highest mean PXRF and ICP concentrations (e.g., Zn, Pb, Cd, Fe), with the exceptions of K and Cl. Validation statistics indicate that the stable validation predictive capacity of PXRF increased in the following order: oven dry intact < field moist < oven dried and powdered. Even under field moist conditions, PXRF could reasonably be used for the determination of Zn (coefficient of determination, R2val 0.86; residual prediction deviation, RPD 2.72) and Cu (R2val 0.77; RPD 2.12), while dried and powdered samples allowed for stable validation prediction of Pb (R2val 0.90; RPD 3.29), Fe (R2val 0.80; RPD 2.29), Cd (R2val 0.75; RPD 2.07) and Cu (R2val 0.98; RPD of 8.53). Summarily, PXRF was shown to be a useful approach for quickly assessing the elemental concentration in vegetation. Future PXRF/vegetation research should explore additional elements and investigate its usefulness in evaluating phytoremediation effectiveness.
The current study describes a simple and rapid method for the direct determination of Ca and P in mineral supplements for cattle by wavelength dispersive - X-ray fluorescence (WD-XRF). For calibration, solid standards obtained through a set of reference materials (RMs) of mineral supplements for cattle with concentrations of Ca ranged from 120 to 223 g kg− 1 (r = 0.9809) and P ranged from 29 to 95 g kg− 1 (r = 0.9957) were used. For Ca, the matrix-matching using the RM 18/03 diluted in Na2CO3: NaCl (1:1 w/w) in the range of 0–204 g kg− 1 (r = 0.9975) was also used as calibration strategy. The proposed method presented limits of detection of 47 mg kg− 1 for Ca and 36 mg kg− 1 for P using calibrations with RMs and 61 mg kg− 1 to Ca using matrix-matching calibration strategy. Accuracy was assessed by the analysis of four RM of mineral supplements for cattle. A statistical evaluation using student's t-test showed that there is no significant difference between the value obtained with the proposed method and the certified value, at 95% confidence level. The method was successfully applied and is a good alternative to conventional acid digestion routine analysis for determination of Ca and P in mineral supplements for cattle.
The effects of foliar-applied ZnO nanoparticles (NPs) and ZnSO4 on winter wheat (Triticum aestivum L.) grain yield and grain quality were studied under field conditions, with the distribution and speciation of Zn within the grain examined using synchrotron-based X-ray fluorescence microscopy and X-ray absorption spectroscopy. Although neither of the two Zn compounds improved grain yield or quality, both increased the grain Zn concentration (average increments were 5 and 10 mg/kg for ZnSO4 and ZnO NPs treatments, respectively). Across all treatments, this Zn was mainly located within the aleurone layer and crease of the grain, although the application of ZnO NPs also slightly increased Zn within the endosperm. This Zn within the grain was found to be present as Zn phosphate, regardless of the form in which the Zn was applied. These results indicate that the foliar-application of ZnO NPs appears to be a promising approach for Zn bio-fortification as required to improve human health.
One of the grand challenges in modern agriculture is increasing biomass production, while improving plant product quality, in a sustainable way. Of the minerals, iron (Fe) plays a major role in this process because it is essential both for plant productivity and for the quality of their products. Fe homeostasis is an important determinant of photosynthetic efficiency in algae and higher plants, and we review here the impact of Fe limitation or excess on the structure and function of the photosynthetic apparatus. We also discuss the agronomic, plant breeding, and transgenic approaches that are used to remediate Fe deficiency of plants on calcareous soils, and suggest ways to increase the Fe content and bioavailability of the edible parts of crops to improve human diet.
Several studies have suggested that the majority of iron (Fe) and zinc (Zn) in wheat grains is associated with phytate, but a nuanced approach to unravel important tissue-level variation in element speciation within the grain is lacking. Here, we present spatially resolved Fe-speciation data obtained directly from different grain tissues using the newly developed synchrotron-based technique of XANES imaging, coupling this with high-definition μ-X-ray fluorescence microscopy (XFM) to map the co-localization of essential elements. In the aleurone, phosphorus (P) is co-localized with Fe and Zn and XANES imaging confirmed that Fe is chelated by phytate in this tissue layer. In the crease tissues, Zn is also positively related to P distribution, albeit less so than in the aleurone. Speciation analysis suggests that Fe is bound to nicotianamine rather than phytate in the nucellar projection and that more complex Fe-structures may also be present. In the embryo, high Zn concentrations are present in the root and shoot primordium, co-occurring with sulfur, and presumably bound to thiol-groups. Overall, Fe is mainly concentrated in the scutellum and co-localized with P. This high resolution imaging and speciation analysis reveals the complexity of the physiological processes responsible for element accumulation and bioaccessibility.
Parboiled rice is known to contain higher levels of nutrients than its non-parboiled counterpart. In order to study the diffusion of micronutrients into the starchy endosperm of the parboiled rice kernel, the parboiled paddy samples were prepared by combining different hydrothermal treatments (hydrated only, steamed-only, hydrated then steamed) employing two hydration temperatures (60 °C and 90 °C). The rice kernels were sectioned longitudinally into 90 μm thick sections after hydrothermal treatment, drying and milling. These rice kernels sections were analysed by Synchrotron X-Ray Fluorescence Microscopy (S-XFM) to determine the distribution of iron (Fe), manganese (Mn), potassium (K) and zinc (Zn). The S-XFM results showed that the bran and germ were rich in these minerals whereas the endosperm had a low concentration. Hydrothermal treatment of kernels increased the mineral diffusion into the endosperm from the bran layer and germ. The highest diffusion of Fe, Zn and Mn was observed in the sample treated with high temperature hydration for a longer time followed by steaming. However, K did not appear to diffuse into the endosperm as much as other the minerals.
The present study on accumulation of heavy metals in the vegetables viz. Beta vulgaris, Phaseolus vulgaris, Spinacea oleracea, and Brassica oleracea var. botrytis grown in the wastewater-irrigated soil near the Bindal river, Dehradun, has shown the maximum accumulation of metals for Pb (196.91 ± 8.13 mg/kg), Cu (36.75 ± 6.19 mg/kg), Zn (305.54 ± 14.30 mg/kg), Ni (125.48 ± 5.97 mg/kg), Cd (29.58 ± 4.26 mg/kg), and Cr (93.06 ± 3.25 mg/kg) in agricultural soil irrigated with wastewater. The enrichment factor of soil was maximum for Cr (8.74) and minimum for Cu (0.88). In case of vegetables, the concentrations of heavy metals were maximum for Pb (86.69 ± 6.69) in the flower of B. oleracea var. botrytis, Cu (33.49 ± 2.09) and Zn (161.86 ± 17.79) in the leaves of S. oleracea, Ni (80.72 ± 8.40) and Cd (23.19 ± 2.76), and Cr (57.18 ± 8.16) in the root of B. vulgaris grown in wastewater (WW)-irrigated soil. The bioaccumulation factor (BAF) for Cu (0.911) was maximum in S. oleracea and minimum for Pb (0.440) in B. vulgaris. The maximum daily intake of metals was found for Zn (0.059) in S. oleracea and minimum for Cd (0.008) in B. vulgaris. The human health risk index was found to be more than 1 for Pb and Cd. The long-term wastewater irrigation resulted in accumulation of heavy metals in vegetables which may cause potential health risks to consumers as these vegetables are sold in local markets of Dehradun city.
For the past century, ferroalloy industries in Brescia province, Italy produced particulate emissions enriched in manganese (Mn), lead (Pb), zinc (Zn), copper (Cu), cadmium (Cd), chromium (Cr), iron (Fe), and aluminum (Al). This study assessed metal concentrations in soil and vegetables of regions with varying ferroalloy industrial activity levels.
Home gardens (n=63) were selected in three regions of varying ferroalloy plant activity durations in Brescia province. Total soil metal concentration and extractability were measured by X-Ray Fluorescence (XRF), aqua regia extraction, and modified Community Bureau of Reference (BCR) sequential extraction. Unwashed and washed spinach and turnips cultivated in the same gardens were analyzed for metal concentrations by flame atomic absorption spectrometry.
Median soil Al, Cd, Fe, Mn, Pb, and Zn concentrations were significantly higher in home gardens near ferroalloy plants compared to reference home gardens. The BCR method yielded the most mobile soil fraction (the sum of extractable metals in Fractions 1 and 2) and all metal concentrations were higher in ferroalloy plant areas. Unwashed spinach showed higher metal concentrations compared to washed spinach. However, some metals in washed spinach were higher in the reference area likely due to history of agricultural product use. Over 60% of spinach samples exceeded the 2- to 4-fold Commission of European Communities and Codex Alimentarius Commission maximum Pb concentrations, and 10% of the same spinach samples exceeded 2- to 3-fold maximum Cd concentrations set by both organizations. Turnip metal concentrations were below maximum standard reference values.
Prolonged industrial emissions increase median metal concentrations and most soluble fractions (BCR F1+F2) in home garden soils near ferroalloy plants. Areas near ferroalloy plant sites had spinach Cd and Pb metal concentrations several-fold above maximum standard references. We recommend thorough washing of vegetables to minimize metal exposure.
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Physical and chemical properties of soils play a major role in the evaluation of different geochemical signature, soil quality, discrimination of land use type, soil provenance and soil degradation. The objectives of the present study are the soil elemental characterization and soil differentiation in topographic sequence and depth, using Energy Dispersive X-Ray Fluorescence (EDXRF) as well as gamma-ray spectrometry data combined with Principal Component Analysis (PCA). The study area is an agricultural region of Boa Vista catchment which is located at Guamiranga municipality, Brazil. PCA analysis was performed with four different data sets: spectral data from EDXRF, spectral data from gamma-ray spectrometry, concentration values from EDXRF measurements and concentration values from gamma-ray spectrometry. All PCAs showed similar results, confirmed by hierarchical cluster analysis, allowing the data grouping into top, bottom and riparian zone samples, i.e. the samples were separated due to its landscape position. The two hillslopes present the same behavior independent of the land use history. There are distinctive and characteristic patterns in the analyzed soil. The methodologies presented are promising and could be used to infer significant information about the region to be studied.
One of the grand challenges in modern agriculture is increasing biomass production, while improving plant product quality, in a sustainable way. Of the minerals, iron (Fe) plays a major role in this process because it is essential both for plant productivity and for the quality of their products. Fe homeostasis is an important determinant of photosynthetic efficiency in algae and higher plants, and we review here the impact of Fe limitation or excess on the structure and function of the photosynthetic apparatus. We also discuss the agronomic, plant breeding, and transgenic approaches that are used to remediate Fe deficiency of plants on calcareous soils, and suggest ways to increase the Fe content and bioavailability of the edible parts of crops to improve human diet.
To assess the applicability of portable X-ray fluorescence (PXRF) spectrometry for metals analysis, total concentrations of As, Pb, Cu, and Zn in 47 agricultural soils were determined using in situ PXRF analysis, ex situ PXRF analysis, and conventional laboratory analysis. The correlation regression parameters of PXRF data with the data of conventional analysis were significantly improved upon going from in situ to ex situ, indicating that improvement of the ex situ PXRF data quality was achieved thorough sample preparation. Use of PXRF in situ was inferior to other analyses, especially when attempting to quantify relatively low levels of metals in agricultural soils. A high degree of linearity and similar spatial distribution existed between ex situ PXRF and laboratory analysis, suggesting that PXRF can be used in rapid detection or screening of agricultural soils, but is best followed with additional sample preparation ex situ and laboratory confirmation.
To maintain cellular homeostasis, concentrations, chemical speciation, and localization of mineral nutrients and toxic trace elements need to be regulated. Imaging the cellular and subcellular localization of elements and measuring their in situ chemical speciation are challenging tasks that can be undertaken using synchrotron-based techniques, such as X-ray fluorescence and X-ray absorption spectrometry, and mass spectrometry-based techniques, such as secondary ion mass spectrometry and laser-ablation inductively coupled plasma mass spectrometry. We review the advantages and limitations of these techniques, and discuss examples of their applications, which have revealed highly heterogeneous distribution patterns of elements in different cell types, often varying in chemical speciation. Combining these techniques with molecular genetic approaches can unravel functions of genes involved in element homeostasis.
Purpose
This contribution reviews the evolution of sediment source fingerprinting investigations since the beginning of such studies in the mid-1970s. Attention is directed to key advances and developments during this period, to the present status of source fingerprinting techniques and to the scope for future development.
Scope
An analysis of the number of papers reporting sediment source fingerprinting investigations or associated methodologies published annually since the mid-1970s to date indicates that the number of such papers has increased near exponentially. The key drivers behind the expansion of such work are examined and linked to both the progress of academic enquiry and the need to support the development of sediment management strategies aimed at countering environmental problems associated with fine sediment. Instead of providing a chronological review of the various advances and developments evidenced by the expanding literature, attention focuses on seven key areas of development which are seen as having together contributed to the current state of the art. These include the expanding range of fingerprint properties employed; the use of statistical tests to confirm the ability of particular fingerprint properties to discriminate between potential sources and to assist in the selection of the ‘best’ properties for inclusion in the final composite fingerprint; the use of numerical mixing models to obtain quantitative estimates of the relative contribution of different sources; recognition of the need to confirm the conservative behaviour of the sediment properties employed as fingerprints and to take account of contrasts in grain size composition and organic matter content between source material and target samples; extension of the approach to include a greater range of targets and potential sources; addition of a temporal dimension, in order to consider changes in sediment source through time; and recognition of the need to direct increased attention to the uncertainty associated with the results of such studies. At the present time, sediment source fingerprinting techniques can be seen as being in a transition from a scientific tool to an operational or management tool, but further development will be required before successful transition to the latter can be fully achieved.
This review comments on the ever expanding range of work using the XRF group of techniques published approximately between April 2012 and March 2013. It presents innovative work as opposed to the wealth of contributions that combine XRF spectrometry in conjunction with other analytical techniques and those descriptions of the valuable routine applications published during the review period. New specialised laboratory instruments, X-ray sources and data processing procedures have been introduced as well as further detector development. Portable and hand-held systems have been increasingly used and the literature represents the widening application of μ-SR techniques for XRF mapping and insights of the sub-cellular metabolisms of animals and plants. Applications using TXRF were published dealing with samples from the pharmaceutical industry, biological tissues, extraterrestrial samples and the analysis of nuclear fuels. Nano-particles feature in many applications and this review is enlivened by reports on more space missions. Climate change, environmental studies and green chemistry feature along with work on archaeological and cultural heritage samples including the authentication of an eighteenth century harpsichord varnish.
Portable X-ray fluorescence (PXRF) can provide a rapid and nondestructive analysis for environmentally important elements in plant matrices. No previous publication has been able to demonstrate the application of PXRF element determination in plant material. To assess the applicability of PXRF for total element analysis, four plant species of agricultural importance {corn (maize) [Zea mays L.], cotton [Gossypium hirsutum L.], soybean [Glycine max (L.) Merr.], and wheat [Triticum aestivum L.]} were collected across northern New South Wales (NSW), Australia. The effect of scanning time and particle size on data quality was also evaluated. For three plant species (corn, cotton, and soybean) there were significant linear relationships between the acid digest values and the PXRF readings for Ca, Co, Cr, Fe, K, Mn, Ni, P, S, Si, and Zn. Only slight reductions in the regression coefficient (r(2)) for Fe and Zn were observed in cotton when scanning time was reduced by more than half. Similar regressions between corn and cotton at 120 s demonstrated the potential for a single algorithm for plant matrices. The use of novel techniques to optimize PXRF settings for quantitative determination of total plant elements provides an efficient alternative to traditional plant digestion.